login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A081913
a(n) = 2^n*(n^3 - 3n^2 + 2n + 48)/48.
3
1, 2, 4, 9, 24, 72, 224, 688, 2048, 5888, 16384, 44288, 116736, 301056, 761856, 1896448, 4653056, 11272192, 27000832, 64028672, 150470656, 350748672, 811597824, 1865416704, 4261412864, 9680453632, 21877489664, 49207574528
OFFSET
0,2
COMMENTS
Binomial transform of A050407, (starting with 1,1,1,2,5,...). 2nd binomial transform of (1,0,0,1,0,0,0,0,...). Case k=2 where a(n,k) = k^n*(n^3 - 3n^2 + 2n + 6k^3)/(6k^3), with g.f. (1 - 3kx + 3k^2x^2 - (k^3-1)x^3)/(1-kx)^4.
FORMULA
a(n) = 2^n*(n^3 - 3n^2 + 2n + 48)/48.
G.f.: (1 - 6x + 12x^2 - 7x^3)/(1-2x)^4.
PROG
(Magma) [2^n*(n^3-3*n^2+2*n+48)/48: n in [0..40]]; // Vincenzo Librandi, Apr 27 2011
CROSSREFS
Cf. A081914.
Sequence in context: A200966 A148084 A156804 * A092236 A367112 A336023
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Mar 31 2003
STATUS
approved