A367877 - OEIS

%I #8 Dec 04 2023 06:37:43

%S 1,1,-3,-17,-7,331,1669,-2561,-82447,-411821,1602941,38344615,

%T 209694121,-1133998085,-29424823819,-194721585329,978185645537,

%U 33795275629219,290738927334637,-827164853506313,-53319390538573159,-621202281347942069,-249829452752930203

%N Expansion of e.g.f. exp(x * (3 - 2*exp(x))).

%F G.f.: Sum_{k>=0} (-2*x)^k / (1 - (k+3)*x)^(k+1).

%F a(n) = Sum_{k=0..n} (-2)^k * (k+3)^(n-k) * binomial(n,k).

%o (PARI) a(n) = sum(k=0, n, (-2)^k*(k+3)^(n-k)*binomial(n, k));

%Y Cf. A367876.

%K sign,easy

%O 0,3

%A _Seiichi Manyama_, Dec 03 2023