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A050915 a(n) = n*4^n + 1. 4
1, 5, 33, 193, 1025, 5121, 24577, 114689, 524289, 2359297, 10485761, 46137345, 201326593, 872415233, 3758096385, 16106127361, 68719476737, 292057776129, 1236950581249, 5222680231937, 21990232555521, 92358976733185 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

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

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

From Colin Barker, Oct 14 2012: (Start)

a(n) = 9*a(n-1) - 24*a(n-2) + 16*a(n-3).

G.f.: -(12*x^2 - 4*x + 1)/((x-1)*(4*x-1)^2). (End)

E.g.f.: exp(x)*(1 + 4*exp(3*x)*x). - Stefano Spezia, Jan 05 2020

MATHEMATICA

CoefficientList[Series[-(12 x^2 - 4 x + 1)/((x - 1) (4 x - 1)^2), {x, 0, 21}], x] (* Michael De Vlieger, Jan 04 2020 *)

PROG

(MAGMA) [ n*4^n+1: n in [0..30]]; // Vincenzo Librandi, Sep 16 2011

CROSSREFS

Cf. A002064.

Sequence in context: A270726 A308679 A272833 * A091056 A244901 A197675

Adjacent sequences:  A050912 A050913 A050914 * A050916 A050917 A050918

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Dec 30 1999

STATUS

approved

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Last modified May 16 09:28 EDT 2021. Contains 343940 sequences. (Running on oeis4.)