OFFSET
4,2
LINKS
Andrew Howroyd, Table of n, a(n) for n = 4..500
FORMULA
From Andrew Howroyd, May 05 2020: (Start)
a(n) = n*A000498(n-1).
a(n) = n*(4^(n-1) - n*3^(n-1) + binomial(n,2)*2^(n-1) - binomial(n,3)). (End)
PROG
(PARI) a(n) = {n*(4^(n-1) - n*3^(n-1) + binomial(n, 2)*2^(n-1) - binomial(n, 3))} \\ Andrew Howroyd, May 05 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 21 2009
EXTENSIONS
Terms a(17) and beyond from Andrew Howroyd, May 05 2020
STATUS
approved