A036542 a(n) = T(n, n), array T given by A047858.

1, 3, 11, 34, 93, 236, 571, 1338, 3065, 6904, 15351, 33782, 73717, 159732, 344051, 737266, 1572849, 3342320, 7077871, 14942190, 31457261, 66060268, 138412011, 289406954, 603979753, 1258291176, 2617245671, 5435817958, 11274289125, 23353884644, 48318382051

Offset

0,2

Links

Colin Barker, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (6,-13,12,-4).

Formula

a(n) = 3*n * 2^(n-1) - n + 1.

From Colin Barker, Feb 20 2016: (Start)

a(n) = 6*a(n-1)-13*a(n-2)+12*a(n-3)-4*a(n-4) for n>3.

G.f.: (1-3*x+6*x^2-5*x^3) / ((1-x)^2*(1-2*x)^2).

(End)

Mathematica

LinearRecurrence[{6, -13, 12, -4}, {1, 3, 11, 34}, 40] (* Harvey P. Dale, Jul 21 2024 *)

Prog

(PARI) Vec((1-3*x+6*x^2-5*x^3)/((1-x)^2*(1-2*x)^2) + O(x^40)) \\ Colin Barker, Feb 20 2016

Crossrefs

Sequence in context: A018413 A004662 A247103 * A084266 A357592 A052471

Adjacent sequences: A036539 A036540 A036541 * A036543 A036544 A036545

Keyword

nonn,easy

Author

Clark Kimberling

Status

approved