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uban numbers
A number  $n$  is called uban if its name (in English) does not contain the letter "u".

In particular, it cannot contain the terms "four", "hundred", and "thousand", So the uban number following 99 is 1000000.

Despite being quite sparse, the sum of the reciprocals of uban numbers slowly diverges.

Uban numbers belong to the same family of aban numbers, eban numbers, iban numbers, and oban numbers. All quite boring, if I may speak my mind...

As for the above sets, the definition is not really precise, since large numbers may have non-standard names.

The first uban numbers are 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15, 16, 17, 18, 19, 20, 21, 22, 23, 25 more terms

Uban numbers can also be... (you may click on names or numbers and on + to get more values)

a-pointer 11 13 2000093 + 9099000089 ABA 18 32 50 + 8056098000000 aban 10 11 12 + 1000000000000 abundant 12 18 20 + 50000000 Achilles 72 2000000 5000000 + 50000000000000 admirable 12 20 30 + 99000042 alt.fact. 19 alternating 10 12 16 + 98 amenable 12 13 16 + 1000000000 arithmetic 11 13 15 + 9000099 astonishing 15 27 automorphic 25 76 balanced p. 53 1000099 6000047 + 9099000013 Bell 15 52 bemirp 1088016000011 1088019000011 16068066000061 19098099000091 betrothed 48 75 binomial 10 15 20 + 8088059000035 brilliant 10 15 21 + 89000071 c.decagonal 11 31 61 + 81052016000051 c.heptagonal 22 43 71 + 56000098000043 c.nonagonal 10 28 55 + 98000077000015 c.octagonal 25 49 81 + 98010099000025 c.pentagonal 16 31 51 + 90000075000016 c.square 13 25 41 + 98000098000025 c.triangular 10 19 31 + 96000060000010 cake 15 26 42 93 Carol 47 Catalan 42 Chen 11 13 17 + 98000059 congruent 13 15 20 + 9000095 constructible 10 12 15 + 96 cube 27 1000000 8000000 + 27000000000000 Cullen 25 65 Cunningham 10 15 17 + 98010099000026 Curzon 18 21 26 + 99000090 cyclic 11 13 15 + 9000097 D-number 15 21 33 + 7000041 d-powerful 43 63 89 de Polignac 1000061 1000099 2000039 + 99000077 decagonal 10 27 52 + 36000087000052 deceptive 91 17000017 41000041 + 41000000041 deficient 10 11 13 + 9000099 dig.balanced 10 11 12 + 69000020 double fact. 15 48 droll 72 Duffinian 16 21 25 + 9000099 eban 30 32 36 + 66066066000066 economical 10 11 13 + 20000000 emirp 13 17 31 + 99000037 emirpimes 15 26 39 + 99000089 enlightened 25000000 25000000000 equidigital 10 11 13 + 19000099 eRAP 20 98 8066000045 esthetic 10 12 21 + 98 Eulerian 11 26 57 66 evil 10 12 15 + 1000000001 fibodiv 19 28 47 + 75 Fibonacci 13 21 55 89 Friedman 25 frugal 1000000 2000000 2000033 + 98000000 gapful 1000000 1000005 1000008 + 99099000099 Gilda 29 49 78 Giuga 30 good prime 11 17 29 + 93000097 happy 10 13 19 + 10000000 harmonic 28 Harshad 10 12 18 + 10000000000 heptagonal 18 55 81 + 90000081000018 hex 19 37 61 + 75000075000019 hexagonal 15 28 45 + 98000077000015 highly composite 12 36 48 60 hoax 22 58 85 + 99000083 Hogben 13 21 31 + 96040049000007 Honaker 17000077 26000069 37000097 + 77000081 house 32 78 hungry 17 hyperperfect 21 28 iban 10 11 12 + 77 iccanobiF 13 39 idoneal 10 12 13 + 93 impolite 16 32 inconsummate 62 63 65 + 95 interprime 12 15 18 + 99000090 Jacobsthal 11 21 43 85 Jordan-Polya 12 16 32 + 96 junction 1000001 1000003 1000005 + 99000070 Kaprekar 45 55 99 50000005000000 katadrome 10 20 21 + 98 Kynea 23 79 Lehmer 15 51 85 + 21025000099 Leyland 17 32 57 20000000000 lonely 23 53 Lucas 11 18 29 + 76 lucky 13 15 21 + 9000079 Lynch-Bell 12 15 36 48 m-pointer 23 61 magic 15 65 magnanimous 11 12 16 + 98 metadrome 12 13 15 + 89 modest 13 19 23 + 1000000099 Moran 18 21 27 + 96000039 Motzkin 21 51 nialpdrome 10 11 20 + 99000000000000 nonagonal 46 75 5040039000075 + 56000046000009 nude 11 12 15 + 99 O'Halloran 12 20 36 60 oban 10 11 12 + 99 octagonal 21 40 65 + 78030051000008 odious 11 13 16 + 1000000000 Ormiston 37000079 37000097 58000013 + 1063000097 palindromic 11 22 33 + 99000099000099 palprime 11 19000000091 32000000023 + 9000007000009 pancake 11 16 22 + 98000091000022 panconsummate 10 11 12 + 91 pandigital 11 15 19 + 69000020 partition 11 15 22 + 77 pentagonal 12 22 35 + 96000092000022 perfect 28 pernicious 10 11 12 + 9000093 Perrin 10 12 17 + 90 Pierpont 13 17 19 + 97 plaindrome 11 12 13 + 99 Poulet 17002089000001 power 16 25 27 + 49098049000000 powerful 16 25 27 + 99099040000000 practical 12 16 18 + 10000000 prim.abundant 12 18 20 + 99000042 prime 11 13 17 + 1000000000039 primeval 13 37 primorial 30 pronic 12 20 30 + 96040049000006 Proth 13 17 25 + 57031000065 pseudoperfect 12 18 20 + 1000000 rare 65 repdigit 11 22 33 + 99 repfigit 19 28 47 + 75 repunit 13 15 21 + 96040049000007 Ruth-Aaron 15 16 25 + 78 Saint-Exupery 60 60000000 2040000000 + 83086080000000 self 20 31 42 + 1000000005 self-describing 22 semiprime 10 15 21 + 99000097 sliding 11 20 25 + 70000000000000 Smith 22 27 58 + 99000083 sphenic 30 42 66 + 99000098 square 16 25 36 + 98010099000025 star 13 37 73 + 96000072000013 strobogrammatic 11 69 88 + 99000096000066 strong prime 11 17 29 + 99000023 super Niven 10 12 20 + 48048000000 super-d 19 31 69 + 9000081 superabundant 12 36 48 60 tau 12 18 36 + 1000000000 taxicab 27000008 1027000000 6013000000 + 98027053000000 tetrahedral 10 20 35 56 tetranacci 15 29 56 triangular 10 15 21 + 98000091000021 tribonacci 13 81 trimorphic 25 49 51 + 50000000000001 truncatable prime 13 17 23 + 97 twin 11 13 17 + 97000021 Ulam 11 13 16 + 10000087 unprimeable 1000010 1000012 1000015 + 10000000 untouchable 52 88 96 upside-down 19 28 37 + 91 wasteful 12 18 20 + 9000099 weak prime 13 19 23 + 99000079 weakly prime 13075000087 72047000057 95053000019 96053000053 weird 70 Woodall 17 23 63 80 Zuckerman 11 12 15 36 Zumkeller 12 20 28 + 96 zygodrome 11 22 33 + 99000099000099