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 A056738 #4 Mar 30 2012 17:30:26
%S A056738 1,4,8,13,20,28,37,47,59,72,86,101,117,135,154,174,195,217,240,264,
%T A056738 290,317,345,374,404,435,467,500,535,571,608,646,685,725,766,808,851,
%U A056738 896,942,989,1037,1086,1136,1187,1239,1292,1346,1402,1459,1517,1576,1636
%N A056738 Positions where 2's occur in A056731.
%F A056738 A056738(n) = A005228(n)+A030124(n)-n-1.
%F A056738 a(n+1) = a(n) + (n+1) + the number of a(k)'s <= n, 1 <= k <= n and a(1) = 1.
%e A056738 a(9) = a(8) + 8 + the number of a(k)'s <= 8 = 47 + 8 + 1 + 3 ( a(3) is <= 8) = 59.
%t A056738 f[1] = 1; f[n_] := f[n] = Block[ {k = 1}, While[ f[k] < n, k++ ]; Return[ f[n - 1] + n + k ]]; Table[ f[n], {n, 0, 60} ]
%K A056738 nonn,easy
%O A056738 1,2
%A A056738 _N. J. A. Sloane_, Aug 31 2000
%E A056738 More terms from _Robert G. Wilson v_, Nov 25 2001