A195857 a(n) = T(9,n), array T given by A047858.

1, 11, 32, 76, 168, 360, 760, 1592, 3320, 6904, 14328, 29688, 61432, 126968, 262136, 540664, 1114104, 2293752, 4718584, 9699320, 19922936, 40894456, 83886072, 171966456, 352321528, 721420280, 1476395000, 3019898872, 6174015480, 12616466424, 25769803768

Offset

0,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..3000

Index entries for linear recurrences with constant coefficients, signature (5,-8,4).

Formula

a(n) = 2^(n-1)*(n+18) - 8.

a(n) = 5*a(n-1) - 8*a(n-2) + 4*a(n-3), a(0)=1, a(1)=11, a(2)=32.

G.f.: (1+6*x-15*x^2)/((1-x)*(1-2*x)^2). - Colin Barker, Aug 24 2016

E.g.f.: exp(x)*(exp(x)*(9 + x) - 8). - Elmo R. Oliveira, Oct 29 2025

Prog

(Magma) [2^(n-1)*(n+18)-8: n in [0..30]];
(PARI) Vec((1+6*x-15*x^2)/((1-x)*(1-2*x)^2) + O(x^40)) \\ Colin Barker, Aug 24 2016

Crossrefs

Cf. A047858.

Sequence in context: A059134 A215727 A007790 * A048773 A056123 A006655

Adjacent sequences: A195854 A195855 A195856 * A195858 A195859 A195860

Keyword

nonn,easy

Author

Vincenzo Librandi, Sep 28 2011

Status

approved