OFFSET
1,2
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..200
Index entries for linear recurrences with constant coefficients, signature (45,-375,875).
FORMULA
a(n) = (11*35^(n-1) - 11*5^(n-1) - 12*(n-1)*5^(n-1))/90. - Andrew Howroyd, May 10 2020
From Colin Barker, Jul 16 2020: (Start)
G.f.: x^2*(3 + 5*x) / ((1 - 5*x)^2*(1 - 35*x)).
a(n) = 45*a(n-1) - 375*a(n-2) + 875*a(n-3) for n>3.
(End)
PROG
(PARI) a(n) = {(11*35^(n-1) - 11*5^(n-1) - 12*(n-1)*5^(n-1))/90} \\ Andrew Howroyd, May 10 2020
(PARI) concat(0, Vec(x^2*(3 + 5*x) / ((1 - 5*x)^2*(1 - 35*x)) + O(x^20))) \\ Colin Barker, Jul 16 2020
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
R. H. Hardin, Dec 06 2008
EXTENSIONS
Terms a(9) and beyond from Andrew Howroyd, May 10 2020
STATUS
approved