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 (15,-63,49).
FORMULA
From Alois P. Heinz, Feb 19 2021: (Start)
G.f.: (56*x^2-21*x+1)/((x-1)*(7*x-1)^2).
a(n) = A036293(n) - 1. (End)
MAPLE
k:= 7; f:= gfun:-rectoproc({1 + (k-1)*n + k*n*a(n-1) - (n-1)*a(n) = 0, a(1) = k-1}, a(n), remember): map(f, [$1..20]); # Georg Fischer, Feb 19 2021
MATHEMATICA
Table[n 7^n-1, {n, 20}] (* or *) LinearRecurrence[{15, -63, 49}, {6, 97, 1028}, 20] (* Harvey P. Dale, Feb 12 2022 *)
PROG
(Magma) [ n*7^n-1: n in [1..20]]; // Vincenzo Librandi, Sep 16 2011
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Oct 19 2001
STATUS
approved