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 A159879 #9 May 28 2021 13:27:07
%S A159879 0,2,11,20,27,36,54,72,74,81,92,101,108,110,128,135,144,153,162,171,
%T A159879 191,200,209,218,225,227,252,254,261,270,317,326,344,353,360,371,387,
%U A159879 405,416,425,504,506,515,540,605,641,684,711,720,722,731,740,767,774,801
%N A159879 Numbers n such that digit sum of n^2 is 2*(digit sum of n).
%C A159879 A007953(n^2) = 2*A007953(n), sod(n^2) = 2*sod(n).
%C A159879 a(n) == {0 or 2} (mod 9). - _Robert G. Wilson v_, May 27 2009
%H A159879 Zak Seidov, <a href="/A159879/b159879.txt">Table of n, a(n) for n=1..3001</a>
%t A159879 fQ[n_] := Plus @@ IntegerDigits[n^2] == 2 Plus @@ IntegerDigits@n; Select[ Range[0, 809], fQ@# &] (* _Robert G. Wilson v_, May 27 2009 *)
%Y A159879 A007953 Digital sum (i.e., sum of digits) of n. A004159 Sum of digits of n^2.
%K A159879 base,nonn
%O A159879 1,2
%A A159879 _Zak Seidov_, Apr 25 2009
%E A159879 Indices in b-file corrected by _N. J. A. Sloane_, Aug 31 2009