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

Author

Vincenzo Librandi, Sep 28 2011

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..3000
• Index entries for linear recurrences with constant coefficients, signature (5,-8,4).

Programs

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

Formula

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

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

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