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 A098690 #18 Aug 30 2021 21:39:36
%S A098690 3,9,24,63,153,362,819,1810,3872,8160,16681,33756,66864,130937,251982,
%T A098690 480793,903981,1685563,3106008,5677863,10276935,18464658,32891187,
%U A098690 58169964,102136772,178096364,308593319,531191384,909227946,1546356485,2617639292
%N A098690 Number of solutions to rev(x^2)=rev(x)^2 below 10^n.
%C A098690 Partial sums of A098701. - _Michel Marcus_, Apr 11 2014
%C A098690 Excludes multiples of 10. - _David Radcliffe_, Aug 28 2021
%C A098690 Also the number of skinny numbers (A061909) with n digits, excluding 0. - _David Radcliffe_, Aug 28 2021
%e A098690 For n = 2 the a(2) = 9 solutions are 1, 2, 3, 11, 12, 13, 21, 22, 31. - _David Radcliffe_, Aug 28 2021
%t A098690 f[n_]:=FromDigits[Reverse[IntegerDigits[n]]];Differences[Table[Length[Select[Range[10^n],f[#^2]==f[#]^2&]],{n,0,6}]] (* _Geoffrey Critzer_, Dec 18 2013 *)
%o A098690 (Python)
%o A098690 def rev(n): return int(str(n)[::-1])
%o A098690 def a(n): return sum(k % 10 and rev(k**2) == rev(k)**2 for k in range(10**n)) # _David Radcliffe_, Aug 28 2021
%Y A098690 Cf. A085305, A225301.
%K A098690 nonn,base
%O A098690 1,1
%A A098690 _Martin Renner_, Oct 27 2004
%E A098690 a(7),a(8) from _Geoffrey Critzer_, Dec 18 2013
%E A098690 Extended using A098701 by _Michel Marcus_, Apr 11 2014