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 A185509 #14 Jul 07 2017 03:45:59
%S A185509 1,6,7,22,41,28,63,146,161,84,154,406,561,476,210,336,966,1526,1631,
%T A185509 1176,462,672,2058,3556,4361,3976,2562,924,1254,4032,7434,9996,10486,
%U A185509 8568,5082,1716,2211,7392,14322,20580,23716,22344,16842,9372,3003,3718,12837,25872,39102,48216,49980,43512,30822,16302,5005,6006,21307,44352,69762,90552,100548,96432,79002,53262,27027,8008,9373,34034,72787,118272,159852
%N A185509 Fourth accumulation array, T, of the natural number array A000027, by antidiagonals.
%C A185509 See A144112 (and A185506) for the definition of rectangular sum array (aa).
%C A185509 Sequence is aa(aa(aa(aa(A000027)))).
%H A185509 G. C. Greubel, <a href="/A185509/b185509.txt">Table of n, a(n) for the first 50 rows, flattened</a>
%F A185509 T(n,k) = F*(5*n^2 + (6*k + 39)*n + 5*k^2 + 9*k + 86), where
%F A185509 F = k*(k+1)*(k+2)*(k+3)*n*(n+1)*(n+2)*(n+3)/86400.
%e A185509 Northwest corner:
%e A185509 1.....6....22....63...154
%e A185509 7....41...146...406...966
%e A185509 28..161...561..1526..3556
%e A185509 84..476..1631..4361..9996
%t A185509 u[n_,k_]:=k(k+1)(k+2)(k+3)n(n+1)(n+2)(n+3)(5n^2+(6k+39)n+5k^2+9k+86)/86400
%t A185509 TableForm[Table[u[n,k],{n,1,10},{k,1,15}]]
%t A185509 Table[u[n-k+1,k],{n,14},{k,n,1,-1}]//Flatten
%Y A185509 Cf. A000027, A185506, A185507, A185508.
%Y A185509 Cf. A000579 (column 1), A257200 (row 1).
%K A185509 nonn,tabl
%O A185509 1,2
%A A185509 _Clark Kimberling_, Jan 29 2011