OFFSET
0,2
COMMENTS
From Omar E. Pol, Jul 18 2012: (Start)
Also sequence found by reading the line from 1, in the direction 1, 14, ..., and the line from 7, in the direction 7, 26, ..., in the square spiral whose vertices are the generalized pentagonal numbers A001318. (End)
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (2,0,-2,1).
FORMULA
G.f.: ( -1-5*x ) / ( (1+x)*(x-1)^3 ). - R. J. Mathar, Oct 26 2011
MATHEMATICA
LinearRecurrence[{2, 0, -2, 1}, {1, 7, 14, 26}, 60] (* Harvey P. Dale, Oct 13 2016 *)
PROG
(PARI) x='x+O('x^50); Vec((-1-5*x)/((1+x)*(x-1)^3)) \\ G. C. Greubel, Jun 19 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Gary W. Adamson, Jun 11 2004
EXTENSIONS
Edited by Don Reble, Nov 16 2005
STATUS
approved