The Eulerian number

, often denoted with

is the number of permutations of the numbers

in which

elements are greater than the previous element, i.e., the number of permutations with
ascents.
For example, among the
permutations of
, there are
permutations with 2 ascents, like
, and
.
Eulerian numbers are given by the formula
and are involved in many indentities, like
The first distinct Eulerian numbers are
1, 4, 11, 26, 57, 66, 120, 247, 302, 502, 1013, 1191, 2036, 2416, 4083, 4293, 8178, 14608, 15619, 16369, 32752, 47840, 65519, 88234, 131054, 152637, 156190 more terms
Pictorial representation of remainders (mod 2, 3, ...,11) frequency. For a table of values and more details
click here
A graph displaying how many Eulerian numbers are multiples of the primes
p from 2 to 71. In black the ideal line 1/
p.