A060416 a(n) = n*4^n - 1, with a(0) = 1.

1, 3, 31, 191, 1023, 5119, 24575, 114687, 524287, 2359295, 10485759, 46137343, 201326591, 872415231, 3758096383, 16106127359, 68719476735, 292057776127, 1236950581247, 5222680231935, 21990232555519, 92358976733183, 387028092977151, 1618481116086271, 6755399441055743

Offset

0,2

Links

Harry J. Smith, Table of n, a(n) for n = 0..200

Paul Leyland, Factors of Cullen and Woodall numbers

Paul Leyland, Generalized Cullen and Woodall numbers

Amelia Carolina Sparavigna, The groupoids of Mersenne, Fermat, Cullen, Woodall and other Numbers and their representations by means of integer sequences, Politecnico di Torino, Italy (2019), [math.NT].

Amelia Carolina Sparavigna, Some Groupoids and their Representations by Means of Integer Sequences, International Journal of Sciences (2019) Vol. 8, No. 10.

Index entries for linear recurrences with constant coefficients, signature (9,-24,16).

Formula

G.f.: (1 - 6*x + 28*x^2 - 32*x^3)/((1 - x)*(1 - 4*x)^2). - Colin Barker, Apr 22 2012

Mathematica

CoefficientList[Series[(1 - 6 x + 28 x^2 - 32 x^3)/((1 - x) (1 - 4 x)^2), {x, 0, 21}], x] (* Michael De Vlieger, Jan 04 2020 *)

Prog

(PARI) a(n) = { abs(n*4^n - 1) } \\ Harry J. Smith, Jul 04 2009

Crossrefs

Sequence in context: A007233 A197892 A198009 * A333368 A060425 A376950

Adjacent sequences: A060413 A060414 A060415 * A060417 A060418 A060419

Keyword

nonn,easy

Author

Jason Earls, Apr 05 2001

Status

approved