OFFSET
1,1
LINKS
Colin Barker, Table of n, a(n) for n = 1..830
Index entries for linear recurrences with constant coefficients, signature (1,254,-254,-1,1).
FORMULA
G.f.: -21*x*(x^4-245*x^2+156*x+10) / ((x-1)*(x^2-16*x+1)*(x^2+16*x+1)).
EXAMPLE
210 is in the sequence because T(20) = 210 = 10+15+21+28+36+45+55 = T(4)+ ... +T(10).
MATHEMATICA
LinearRecurrence[{1, 254, -254, -1, 1}, {210, 3486, 51681, 883785, 13125126}, 30] (* Vincenzo Librandi, Jun 27 2015 *)
PROG
(PARI) Vec(-21*x*(x^4-245*x^2+156*x+10) / ((x-1)*(x^2-16*x+1)*(x^2+16*x+1)) + O(x^100))
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Colin Barker, May 05 2015
STATUS
approved