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 A292871 #12 Feb 12 2019 12:06:45
%S A292871 1,1,5,28,169,1071,7034,47538,329249,2331424,16856915,124387286,
%T A292871 936799582,7204759238,56634639780,455560907508,3755017488657,
%U A292871 31763254337955,276141607672244,2470749459597450,22777862470135279,216542289861590847,2123786397875045480,21490054470340915524,224275454800219674782
%N A292871 a(n) = [x^n] (1/(1 - x - x^2/(1 - 2*x - 2*x^2/(1 - 3*x - 3*x^2/(1 - 4*x - 4*x^2/(1 - ...))))))^n.
%C A292871 a(n) is the n-th term of the n-fold convolution of Bell numbers with themselves. - _Alois P. Heinz_, Feb 12 2019
%H A292871 Alois P. Heinz, <a href="/A292871/b292871.txt">Table of n, a(n) for n = 0..573</a>
%F A292871 a(n) = A292870(n,n).
%F A292871 a(n) = A205574(2n,n).
%p A292871 b:= proc(n, k) option remember; `if`(n=0, 1, `if`(k=0, 0,
%p A292871 `if`(k=1, add(b(n-j, k)*binomial(n-1, j-1), j=1..n),
%p A292871 (h-> add(b(j, h)*b(n-j, k-h), j=0..n))(iquo(k,2)))))
%p A292871 end:
%p A292871 a:= n-> b(n$2):
%p A292871 seq(a(n), n=0..25); # _Alois P. Heinz_, May 31 2018
%t A292871 Table[SeriesCoefficient[1/(1 - x + ContinuedFractionK[-k x^2, 1 - (k + 1) x, {k, 1, n}])^n, {x, 0, n}], {n, 0, 24}]
%Y A292871 Main diagonal of A292870.
%Y A292871 Cf. A000110, A205574.
%K A292871 nonn
%O A292871 0,3
%A A292871 _Ilya Gutkovskiy_, Sep 25 2017