OFFSET
1,1
COMMENTS
Positive integers x in the solutions to 2*x^2-94*y^2-4324*y-67022 = 0.
LINKS
Colin Barker, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (0,96,0,-1).
FORMULA
a(n) = 96*a(n-2)-a(n-4).
G.f.: -94*x*(x^3+x^2-55*x-41) / (x^4-96*x^2+1).
EXAMPLE
3854 is in the sequence because 3854^2 = 14853316 = 539^2+540^2+...+585^2.
MATHEMATICA
LinearRecurrence[{0, 96, 0, -1}, {3854, 5170, 369890, 496226}, 50] (* Vincenzo Librandi, May 11 2015 *)
PROG
(PARI) Vec(-94*x*(x^3+x^2-55*x-41) / (x^4-96*x^2+1) + O(x^100))
(Magma) I:=[3854, 5170, 369890, 496226 ]; [n le 4 select I[n] else 96*Self(n-2)-Self(n-4): n in [1..30]]; // Vincenzo Librandi, May 11 2015
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Colin Barker, May 08 2015
STATUS
approved