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 A061911 #18 Oct 27 2023 22:00:47
%S A061911 1,2,3,3,3,1,2,3,4,4,3,3,2,3,4,4,3,4,3,4,3,3,3,4,4,3,5,4,5,5,4,5,3,5,
%T A061911 4,1,2,3,4,4,3,2,3,4,5,3,4,5,4,4,4,4,4,3,5,5,5,4,5,3,5,4,5,5,2,3,4,4,
%U A061911 3,4,5,4,5,4,4,5,4,4,4,3,5,5,6,4,5,5,5,5,5,5,3,4,4,4,5,3,4,3,5,4,5,4,5,4,3
%N A061911 Square root of the sum of the digits of k^2 when this sum is a square.
%F A061911 a(n) = sqrt(A004159(A061910(n))) = sqrt(A007953((A061910(n))^2)). - _Zak Seidov_, Jul 04 2012
%e A061911 6^2 = 36 and 3+6 = 9 is a square, thus 3 is in the sequence. 13^2 = 169 and 1+6+9 = 16 is a square, thus 4 is in the sequence.
%p A061911 readlib(issqr): f := []: for n from 1 to 200 do if issqr(convert(convert(n^2,base,10),`+`)) then f := [op(f),sqrt(convert(convert(n^2,base,10),`+`))] fi; od; f;
%t A061911 Select[Table[Sqrt[Total[IntegerDigits[n^2]]],{n,350}],IntegerQ] (* _Jayanta Basu_, May 06 2013 *)
%Y A061911 Cf. A007953, A004159, A061909, A061910, A061912.
%K A061911 nonn,base
%O A061911 1,2
%A A061911 _Asher Auel_, May 17 2001