%I M2979 #28 Jan 25 2020 17:59:16
%S 1,1,3,14,97,934,11814,188650,3698399,87133235,2424143590,78483913829,
%T 2920947798710,123676552368689,5904927996501989,315465738505181316,
%U 18730636267115299571,1228583480023634860711,88548597460914590753663,6979070787198903764535472
%N Shifts left when Stirling2 transform is applied twice.
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H Alois P. Heinz, <a href="/A007470/b007470.txt">Table of n, a(n) for n = 1..120</a>
%H M. Bernstein and N. J. A. Sloane, <a href="http://arXiv.org/abs/math.CO/0205301">Some canonical sequences of integers</a>, Linear Alg. Applications, 226-228 (1995), 57-72; erratum 320 (2000), 210. [Link to arXiv version]
%H M. Bernstein and N. J. A. Sloane, <a href="/A003633/a003633_1.pdf">Some canonical sequences of integers</a>, Linear Alg. Applications, 226-228 (1995), 57-72; erratum 320 (2000), 210. [Link to Lin. Alg. Applic. version together with omitted figures]
%H N. J. A. Sloane, <a href="/transforms.txt">Transforms</a>
%p stirtr:= proc(p)
%p proc(n) add(p(k)*Stirling2(n, k), k=0..n) end
%p end:
%p a:= proc(n) option remember; `if`(n<2, 1, aa(n-1)) end:
%p aa:= (stirtr@@2)(a):
%p seq(a(n), n=1..25); # _Alois P. Heinz_, Jun 22 2012
%t stirtr[p_] := Function[{n}, Sum[p[k]*StirlingS2[n, k], {k, 0, n}]]; a[n_] := a[n] = If[n < 2, 1, aa[n-1]]; aa := stirtr[stirtr[a]]; Table[a[n], {n, 1, 25}] (* _Jean-François Alcover_, Oct 30 2013, translated from Alois P. Heinz's Maple program *)
%K nonn,nice,eigen
%O 1,3
%A _N. J. A. Sloane_