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 A048808 #22 May 15 2019 06:42:40
%S A048808 1,1,2,3,5,7,12,18,27,42,64,96,146,219,327,491,730,1084,1608,2376,
%T A048808 3500,5154,7563,11076,16193,23625,34395,50005,72550,105089,151984,
%U A048808 219448,316362,455434,654661,939736,1347137,1928593,2757449,3937675
%N A048808 Number of rooted trees with n nodes with every leaf at height 3.
%H A048808 Vaclav Kotesovec, <a href="/A048808/b048808.txt">Table of n, a(n) for n = 4..10000</a> (terms 4..1000 from Alois P. Heinz)
%H A048808 N. J. A. Sloane, <a href="/transforms.txt">Transforms</a>
%H A048808 <a href="/index/Ro#rooted">Index entries for sequences related to rooted trees</a>
%F A048808 Euler transform of A002865 (with a(0)=0) shifted right.
%t A048808 T[n_, k_] := T[n, k] = If[n == 1, 1, If[k == 0, 0, Sum[Sum[If[d < k, 0, T[d, k - 1]*d], {d, Divisors[j]}]*T[n - j, k], {j, 1, n - 1}]/(n - 1)]];
%t A048808 a[n_] := T[n, 3];
%t A048808 Table[a[n], {n, 4, 50}] (* _Jean-François Alcover_, May 11 2019, after _Alois P. Heinz_ in A244925 *)
%Y A048808 Cf. A048809-A048816.
%Y A048808 Column k=3 of A244925.
%K A048808 nonn
%O A048808 4,3
%A A048808 _Christian G. Bower_, Apr 15 1999