This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A061806 #3 Oct 27 2023 22:00:46
%S A061806 4,5,17,26,28,32,37,40,43,44,49,50,53,62,63,64,67,73,74,76,77,82,83,
%T A061806 86,87,88,89,91,92,93,94,97,98,107,109,113,114,116,117,118,122,124,
%U A061806 125,126,127,128,133,137,141,143,149,154,157,158,161,164,166,167,169,170
%N A061806 Numbers n such that the iterative cycle: n -> sum of digits of n^2 has only three distinct elements.
%e A061806 4 -> 1+6 = 7 -> 4+9 = 13 -> 1+6+9 = 16 -> 2+5+6 = 13, thus {7,13,16} are the only distinct elements of the iterative cycle of 4.
%Y A061806 Cf. A007953, A004159, A061903 - A061910.
%K A061806 nonn,base
%O A061806 1,1
%A A061806 _Asher Auel_, May 17 2001