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 A113046 #14 Jul 25 2017 12:07:34
%S A113046 1,1,3,1,1,3,5,5,6,3,3,3,3,3,3,1,1,9,11,11,12,5,5,15,16,10,12,6,6,9,9,
%T A113046 6,6,3,3,9,9,9,9,3,3,9,9,6,6,3,3,3,3,3,3,1,1,27,29,29,30,11,11,33,34,
%U A113046 22,24,12,12,15,15,12,12,5,5,45,46,28,30,16,16,30,32,23,24,12,12,18,18,12
%N A113046 Diagonal sums of number triangle binomial(n, floor((n-k)/2)) mod 3.
%C A113046 Diagonal sums of A113045.
%H A113046 Antti Karttunen, <a href="/A113046/b113046.txt">Table of n, a(n) for n = 0..10000</a>
%F A113046 a(n) = Sum_{k=0..floor(n/2)} binomial(n-k, floor((n-2k)/2)) mod 3.
%p A113046 A113046:=n->add(binomial(n-k, floor((n-2*k)/2)) mod 3, k=0..floor(n/2)): seq(A113046(n), n=0..150); # _Wesley Ivan Hurt_, Jul 25 2017
%o A113046 (PARI) A113046(n) = sum(k=0,n\2,binomial(n-k,((n-(2*k))\2))%3); \\ _Antti Karttunen_, Jul 24 2017
%Y A113046 Cf. A113045.
%K A113046 easy,nonn
%O A113046 0,3
%A A113046 _Paul Barry_, Oct 11 2005