OFFSET
1,1
COMMENTS
Also nonnegative integers y in the solutions to 18*x^2-3*y^2+24*x+y+18 = 0, the corresponding values of x being A252092.
LINKS
Colin Barker, Table of n, a(n) for n = 1..168
Index entries for linear recurrences with constant coefficients, signature (940899,-940899,1).
FORMULA
a(n) = 940899*a(n-1)-940899*a(n-2)+a(n-3).
G.f.: -18*x*(489*x^2-9206*x+5) / ((x-1)*(x^2-940898*x+1)).
EXAMPLE
90 is in the sequence because P(90) = 12105 = 3816+4033+4256 = N(36)+N(37)+N(38).
PROG
(PARI) Vec(-18*x*(489*x^2-9206*x+5)/((x-1)*(x^2-940898*x+1)) + O(x^100))
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Colin Barker, Dec 14 2014
STATUS
approved