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 A211481 #8 Nov 09 2014 06:32:11
%S A211481 1,3,8,16,26,38,54,71,91,114,139,166,197,229,264,302,342,384,430,477,
%T A211481 527,580,635,692,753,815,880,948,1018,1090,1166,1243,1323,1406,1491,
%U A211481 1578,1669,1761,1856,1954,2054,2156,2262,2369,2479,2592,2707
%N A211481 Number of ordered triples (w,x,y) with all terms in {-n,...,0,...,n} and w+2x+3y=n.
%C A211481 For a guide to related sequences, see A211422.
%F A211481 Conjecture: a(n) = a(n-1)+a(n-2)-a(n-4)-a(n-5)+a(n-6) for n>5. - _Colin Barker_, Nov 08 2014
%F A211481 Empirical g.f.: -(3*x^4+5*x^3+4*x^2+2*x+1) / ((x-1)^3*(x+1)*(x^2+x+1)). - _Colin Barker_, Nov 08 2014
%t A211481 t[n_] := t[n] = Flatten[Table[w + 2 x + 3 y - n, {w, -n, n}, {x, -n, n}, {y, -n, n}]]
%t A211481 c[n_] := Count[t[n], 0]
%t A211481 t = Table[c[n], {n, 0, 70}] (* A211481 *)
%Y A211481 Cf. A211422.
%K A211481 nonn
%O A211481 0,2
%A A211481 _Clark Kimberling_, Apr 12 2012