OFFSET
1,2
LINKS
Colin Barker, Table of n, a(n) for n = 1..208
Index entries for linear recurrences with constant coefficients, signature (0,4162056194,0,-1).
FORMULA
a(n) = 4162056194*a(n-2)-a(n-4).
G.f.: -x*(x-1)*(x^2+16322042*x+1) / ((x^2-64514*x+1)*(x^2+64514*x+1)).
EXAMPLE
16322041 is in the sequence because it is the 2857th hexagonal number and the 2160th centered heptagonal number.
MATHEMATICA
LinearRecurrence[{0, 4162056194, 0, -1}, {1, 16322041, 4145734153, 67933251842771953}, 20] (* Harvey P. Dale, Jan 05 2017 *)
PROG
(PARI) Vec(-x*(x-1)*(x^2+16322042*x+1)/((x^2-64514*x+1)*(x^2+64514*x+1)) + O(x^100))
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Colin Barker, Jan 10 2015
STATUS
approved