A048482 a(n) = T(n,n), array T given by A048472.

1, 3, 13, 49, 161, 481, 1345, 3585, 9217, 23041, 56321, 135169, 319489, 745473, 1720321, 3932161, 8912897, 20054017, 44826625, 99614721, 220200961, 484442113, 1061158913, 2315255809, 5033164801, 10905190401, 23555211265, 50734301185, 108984795137

Offset

0,2

Links

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

Index entries for linear recurrences with constant coefficients, signature (7,-18,20,-8).

Formula

a(n) = 2 * A001788(n) + 1.

a(n) = (n^2+n)*2^(n-1) + 1. - Ralf Stephan, Sep 02 2003

G.f.: -(8*x^3-10*x^2+4*x-1) / ((x-1)*(2*x-1)^3). - Colin Barker, Nov 26 2014

a(0)=1, a(1)=3, a(2)=13, a(3)=49, a(n)=7*a(n-1)-18*a(n-2)+ 20*a(n-3)- 8*a(n-4). - Harvey P. Dale, Feb 02 2015

Mathematica

LinearRecurrence[{7, -18, 20, -8}, {1, 3, 13, 49}, 30] (* Harvey P. Dale, Feb 02 2015 *)

Prog

(Magma) [(n^2+n)*2^(n-1) + 1: n in [0..30]]; // Vincenzo Librandi, Sep 23 2011
(PARI) Vec(-(8*x^3-10*x^2+4*x-1)/((x-1)*(2*x-1)^3) + O(x^100)) \\ Colin Barker, Nov 26 2014

Crossrefs

Cf. A002999, A003013, A001787, A005183, A001788.

Sequence in context: A027326 A108946 A352028 * A094978 A251743 A178934

Adjacent sequences: A048479 A048480 A048481 * A048483 A048484 A048485

Keyword

nonn,easy

Author

Clark Kimberling

Status

approved