OFFSET
1,2
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..500
Index entries for linear recurrences with constant coefficients, signature (13,-58,106,-85,25).
FORMULA
a(n) = n*(2*5^n - 16*n) for n > 1. - Andrew Howroyd, May 04 2020
From Colin Barker, Jul 16 2020: (Start)
G.f.: 2*x^2*(18 + 69*x - 523*x^2 + 255*x^3 - 75*x^4) / ((1 - x)^3*(1 - 5*x)^2).
a(n) = 13*a(n-1) - 58*a(n-2) + 106*a(n-3) - 85*a(n-4) + 25*a(n-5) for n>6.
(End)
PROG
(Magma) [0] cat [ n*(2*5^n - 16*n) : n in [2..30]]; // Wesley Ivan Hurt, Jul 16 2020
(PARI) a(n) = if(n <= 1, 0, n*(2*5^n - 16*n)) \\ Andrew Howroyd, May 04 2020
(PARI) concat(0, Vec(2*x^2*(18 + 69*x - 523*x^2 + 255*x^3 - 75*x^4) / ((1 - x)^3*(1 - 5*x)^2) + O(x^40))) \\ Colin Barker, Jul 16 2020
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
R. H. Hardin, May 21 2009
EXTENSIONS
Terms a(9) and beyond from Andrew Howroyd, May 04 2020
STATUS
approved