A048476 a(n) = T(4,n), array T given by A048472.

1, 6, 21, 61, 161, 401, 961, 2241, 5121, 11521, 25601, 56321, 122881, 266241, 573441, 1228801, 2621441, 5570561, 11796481, 24903681, 52428801, 110100481, 230686721, 482344961, 1006632961, 2097152001, 4362076161, 9059696641, 18790481921, 38923141121

Offset

0,2

Comments

n-th difference of a(n), a(n-1), ..., a(0) is (5, 10, 15, ...).

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

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

Formula

a(n) = 5*n * 2^(n-1) + 1.

a(n) = 5*a(n-1)-8*a(n-2)+4*a(n-3) for n>2. G.f.: (1+x-x^2) / ((1-x)*(1-2*x)^2). - Colin Barker, Feb 18 2016

Prog

(Magma) [5*n * 2^(n-1) + 1: n in [0..30]]; // Vincenzo Librandi, Sep 23 2011
(PARI) Vec((1+x-x^2)/((1-x)*(1-2*x)^2) + O(x^40)) \\ Colin Barker, Feb 18 2016

Crossrefs

Sequence in context: A012593 A276235 A334833 * A122678 A256569 A132130

Adjacent sequences: A048473 A048474 A048475 * A048477 A048478 A048479

Keyword

nonn,easy

Author

Clark Kimberling

Status

approved