OFFSET
1,3
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..200
Index entries for linear recurrences with constant coefficients, signature (16,-69,90).
FORMULA
a(n) = (13*10^(n-1) - 13*3^(n-1) - 14*(n-1)*3^(n-1))/49. - Andrew Howroyd, May 10 2020
From Colin Barker, May 19 2020: (Start)
G.f.: x*(1 + 3*x) / ((1 - 3*x)^2*(1 - 10*x)).
a(n) = 16*a(n-1) - 69*a(n-2) + 90*a(n-3) for n>3.
(End)
PROG
(PARI) a(n) = {(13*10^(n-1) - 13*3^(n-1) - 14*(n-1)*3^(n-1))/49} \\ Andrew Howroyd, May 10 2020
(PARI) concat(0, Vec(x*(1 + 3*x) / ((1 - 3*x)^2*(1 - 10*x)) + O(x^20))) \\ Colin Barker, May 19 2020
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
R. H. Hardin, Dec 06 2008
EXTENSIONS
Terms a(12) and beyond from Andrew Howroyd, May 10 2020
STATUS
approved