A357933 - OEIS

%I #9 Oct 21 2022 10:12:12

%S 1,1,1,1,1,1,2,4,7,11,16,24,40,72,131,231,395,675,1187,2161,4006,7414,

%T 13609,24951,46210,86930,165528,316682,606047,1161343,2237329,4345777,

%U 8507103,16738587,33030166,65352308,129821251,259254283,520531422,1049771054,2124315222

%N a(n) = Sum_{k=0..floor(n/5)} |Stirling1(n - 4*k,n - 5*k)|.

%F G.f.: Sum_{k>=0} x^k * Product_{j=0..k-1} (1 + j * x^4).

%o (PARI) a(n) = sum(k=0, n\5, abs(stirling(n-4*k, n-5*k, 1)));

%o (PARI) my(N=50, x='x+O('x^N)); Vec(sum(k=0, N, x^k*prod(j=0, k-1, 1+j*x^4)))

%Y Cf. A124380, A357931, A357932.

%K nonn

%O 0,7

%A _Seiichi Manyama_, Oct 21 2022