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rare numbers
A number n such that n ± rev(n) are two squares. more

The rare numbers up to 1015 :

Distribution of the remainders when the numbers in this family are divided by n=2, 3,..., 11. (I took into account 84 values, from 65 to 6.5⋅1019).

n\r 0  1 
26618 2 
318066 3 
42018460 4 
523047140 5 
6150513015 6 
721725615118 7 
886460121200 8 
91801400380014 9 
1011041001206140 10 
1141050007164011

A pictorial representation of the table above
motab
Imagine to divide the members of this family by a number n and compute the remainders. Should they be uniformly distributed, each remainder from 0 to n-1 would be obtained in about (1/n)-th of the cases. This outcome is represented by a white square. Reddish (resp. bluish) squares represent remainders which appear more (resp. less) frequently than 1/n.