OFFSET
1,2
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..500
Index entries for linear recurrences with constant coefficients, signature (17,-94,190,-161,49).
FORMULA
a(n) = n*(3*7^n - 36*n) for n > 1. - Andrew Howroyd, May 04 2020
From Colin Barker, Jul 17 2020: (Start)
G.f.: 3*x^2*(50 + 71*x - 1545*x^2 + 805*x^3 - 245*x^4) / ((1 - x)^3*(1 - 7*x)^2).
a(n) = 17*a(n-1) - 94*a(n-2) + 190*a(n-3) - 161*a(n-4) + 49*a(n-5) for n>6.
(End)
PROG
(PARI) a(n) = if(n <= 1, 0, n*(3*7^n - 36*n)) \\ Andrew Howroyd, May 04 2020
(PARI) concat(0, Vec(3*x^2*(50 + 71*x - 1545*x^2 + 805*x^3 - 245*x^4) / ((1 - x)^3*(1 - 7*x)^2) + O(x^40))) \\ Colin Barker, Jul 17 2020
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
R. H. Hardin, May 21 2009
EXTENSIONS
Terms a(7) and beyond from Andrew Howroyd, May 04 2020
STATUS
approved