A093835 n*Jacobsthal(n).

0, 1, 2, 9, 20, 55, 126, 301, 680, 1539, 3410, 7513, 16380, 35503, 76454, 163845, 349520, 742747, 1572858, 3320497, 6990500, 14680071, 30758222, 64312669, 134217720, 279620275, 581610146, 1207959561, 2505397580, 5189752159

Offset: 0

Author

Paul Barry, Apr 20 2004

Keywords

• nonn
• easy

Comments

Convolution of Jacobsthal numbers A001045 and modified Jacobsthal-Lucas numbers (in A014551, change the leading 2 to a 1).

Links

• Index entries for linear recurrences with constant coefficients, signature (2,3,-4,-4).

Crossrefs

Cf. A023607.

Programs

Mathematica

LinearRecurrence[{2,3,-4,-4},{0,1,2,9},30] (* Harvey P. Dale, Jun 17 2017 *)

Formula

G.f.: x(1+2x^2)/(1-x-2x^2)^2; a(n)=n2^n/3-n(-1)^n/3.

a(n) = n*A001045(n). - R. J. Mathar, May 07 2019