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 A218720 #4 Nov 05 2012 12:20:58
%S A218720 0,10,515,296344,35764191,1108900220,316411915250,47023298541694,
%T A218720 3156215819652023,310872228812491206,28124944860980892220,
%U A218720 3783840171259076226254,208193145695151069244665,19364218657938636320485082,663491749602035014400202724
%N A218720 a(n) is smallest number such that a(n)^2 + 1 is divisible by 101^n.
%e A218720 a(3) = 296344 because 296344^2+1 = 101 ^ 3 * 85237.
%t A218720 b=10;n101=101;jo=Join[{0,b},Table[n101=101*n101;b=PowerMod[b, 101,n101];b=Min[b,n101-b],{99}]]
%Y A218720 Cf. A002522, A049532, A034939, A218709, A218710, A218712, A218713, A218714, A218715, A218716, A218717, A218718, A218719.
%K A218720 nonn
%O A218720 0,2
%A A218720 _Michel Lagneau_, Nov 04 2012