A173516 - OEIS

%I #13 Apr 17 2024 00:23:15

%S 1,7,64,769,11536,207649,4360630,104655121,2825688268,84770648041,

%T 2797431385354,100707529872745,3927593665037056,164958933931556353,

%U 7423152026920035886,356311297292161722529,18171876161900247848980

%N a(1)=1, a(n) = 3*n*a(n-1) + 1, n > 1.

%C If s(n) is a sequence defined as s(0) = x, s(n) = 3n*s(n-1)+k then s(n) = 3^n*n!*x + a(n)*k, n > 0.

%F E.g.f.: (exp(x)-1) / (1-3*x). - _Kevin Ryde_, Apr 16 2024

%Y Cf. A002627, A056541.

%K nonn,easy

%O 1,2

%A _Gary Detlefs_, Feb 20 2010