A064752 a(n) = n*6^n - 1.

5, 71, 647, 5183, 38879, 279935, 1959551, 13436927, 90699263, 604661759, 3990767615, 26121388031, 169789022207, 1097098297343, 7052774768639, 45137758519295, 287753210560511, 1828079220031487, 11577835060199423

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Paul Leyland, Factors of Cullen and Woodall numbers

Paul Leyland, Generalized Cullen and Woodall numbers

Index entries for linear recurrences with constant coefficients, signature (13, -48, 36).

Formula

a(n) = 13*a(n-1) - 48*a(n-2) + 36*a(n-3); a(1)=5, a(2)=71, a(3)=647. - Harvey P. Dale, May 25 2011

G.f.: 6*x/(1-6*x)^2+x/(x-1). - Harvey P. Dale, May 25 2011

Mathematica

Table[n 6^n-1, {n, 25}] (* or *) LinearRecurrence[{13, -48, 36}, {5, 71, 647}, 25] (* Harvey P. Dale, May 25 2011 *)

Prog

(Magma) [ n*6^n-1: n in [1..20]]; // Vincenzo Librandi, Sep 16 2011

Crossrefs

Sequence in context: A295536 A197427 A197668 * A033507 A092250 A362159

Adjacent sequences: A064749 A064750 A064751 * A064753 A064754 A064755

Keyword

nonn,easy

Author

N. J. A. Sloane, Oct 19 2001

Status

approved