A323632 - OEIS

%I #13 Aug 06 2021 08:40:39

%S 0,1,2,7,31,152,813,4741,29956,203305,1470795,11276718,91221419,

%T 775677177,6910797962,64326920851,623981351195,6293426736344,

%U 65867162316433,714062197266081,8005397253530924,92676194887133693,1106385117766336919,13603803900252612966,172082332173918135687

%N Stirling transform of Jacobsthal numbers (A001045).

%H Alois P. Heinz, <a href="/A323632/b323632.txt">Table of n, a(n) for n = 0..558</a>

%F E.g.f.: (exp(2*(exp(x) - 1)) - exp(1 - exp(x)))/3.

%F a(n) = Sum_{k=0..n} Stirling2(n,k)*A001045(k).

%F a(n) = (A001861(n) - A000587(n))/3.

%p b:= proc(n, m) option remember;

%p      `if`(n=0, round(2^m/3), m*b(n-1, m)+b(n-1, m+1))

%p     end:

%p a:= n-> b(n, 0):

%p seq(a(n), n=0..24);  # _Alois P. Heinz_, Aug 06 2021

%t nmax = 24; CoefficientList[Series[(Exp[2 (Exp[x] - 1)] - Exp[1 - Exp[x]])/3, {x, 0, nmax}], x] Range[0, nmax]!

%t Table[Sum[StirlingS2[n, k] (2^k - (-1)^k)/3, {k, 0, n}], {n, 0, 24}]

%t Table[(BellB[n, 2] - BellB[n, -1])/3, {n, 0, 24}]

%Y Cf. A000587, A001045, A001861, A263575, A263576.

%K nonn

%O 0,3

%A _Ilya Gutkovskiy_, Jan 21 2019