OFFSET
1,2
COMMENTS
Also nonnegative integers x in the solutions to 8*x^2-4*y^2+4*x+2*y+2 = 0, the corresponding values of y being A251602.
LINKS
Colin Barker, Table of n, a(n) for n = 1..654
Index entries for linear recurrences with constant coefficients, signature (35,-35,1).
FORMULA
a(n) = 35*a(n-1) - 35*a(n-2) + a(n-3).
G.f.: x^2*(5*x-13) / ((x-1)*(x^2-34*x+1)).
a(n) = (-4+(17+12*sqrt(2))^n*(-38+27*sqrt(2))-(17+12*sqrt(2))^(-n)*(38+27*sqrt(2)))/16. - Colin Barker, Mar 02 2016
EXAMPLE
13 is in the sequence because H(13) + H(14) = 325 + 378 = 703 = H(19).
PROG
(PARI) concat(0, Vec(x^2*(5*x-13)/((x-1)*(x^2-34*x+1)) + O(x^20)))
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Colin Barker, Dec 05 2014
STATUS
approved