OFFSET
1,1
LINKS
Colin Barker, Table of n, a(n) for n = 1..642
Index entries for linear recurrences with constant coefficients, signature (1,1298,-1298,-1,1).
FORMULA
a(n) = a(n-1)+1298*a(n-2)-1298*a(n-3)-a(n-4)+a(n-5) for n>5.
G.f.: 13*x*(5*x^4+65*x^3-1947*x^2-65*x-2) / ((x-1)*(x^2-36*x-1)*(x^2+36*x-1)).
EXAMPLE
26 is in the sequence because (26+39)^3 - 26^3 = 507^2.
MATHEMATICA
LinearRecurrence[{1, 1298, -1298, -1, 1}, {26, 871, 59930, 1155895, 77814386}, 20] (* Harvey P. Dale, Mar 25 2020 *)
PROG
(PARI) Vec(13*x*(5*x^4+65*x^3-1947*x^2-65*x-2)/((x-1)*(x^2-36*x-1)*(x^2+36*x-1)) + O(x^30))
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Colin Barker, Oct 30 2015
STATUS
approved