OFFSET
0,3
LINKS
Colin Barker, Table of n, a(n) for n = 0..1000
H. Gupta, On a problem in parity, Indian J. Math., 11 (1969), 157-163. [Annotated scanned copy] See Q(w) on first page.
Index entries for linear recurrences with constant coefficients, signature (7,-17,17,-6).
FORMULA
From Colin Barker, Oct 26 2015: (Start)
a(n) = 7*a(n-1)-17*a(n-2)+17*a(n-3)-6*a(n-4) for n>3.
G.f.: x*(3*x^2-3*x+1) / ((x-1)^2*(2*x-1)*(3*x-1)).
(End)
PROG
(PARI) a(n) = (3^(n+1)-2^(n+2)+2*n+1)/4 \\ Colin Barker, Oct 26 2015
(PARI) concat(0, Vec(x*(3*x^2-3*x+1)/((x-1)^2*(2*x-1)*(3*x-1)) + O(x^40))) \\ Colin Barker, Oct 26 2015
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Oct 23 2015
EXTENSIONS
Typo in last term fixed by Colin Barker, Oct 26 2015
STATUS
approved