|
|
A179483
|
|
A(k,3) where A(k,n) = Sum_{m=1..k} (-1)^(m+1) *binomial(n,m)*m^k.
|
|
1
|
|
|
3, -9, 6, 36, 150, 540, 1806, 5796, 18150, 55980, 171006, 519156, 1569750, 4733820, 14250606, 42850116, 128746950, 386634060, 1160688606, 3483638676, 10454061750, 31368476700, 94118013006, 282379204836, 847187946150, 2541664501740, 7625194831806
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
LINKS
|
|
|
FORMULA
|
G.f.: 3*x*(1 - 9*x + 31*x^2 - 39*x^3 + 18*x^4) / ((1 - x)*(1 - 2*x)*(1 - 3*x)).
a(n) = 3 - 3*2^n + 3^n for n>2.
a(n) = 6*a(n-1) - 11*a(n-2) + 6*a(n-3) for n>5.
(End)
|
|
MAPLE
|
A179483 := proc(n) add( (-1)^(m+1)*binomial(3, m)*m^n, m=1..n) ; end proc: # R. J. Mathar, Jan 31 2011
|
|
MATHEMATICA
|
Sum[(-1)^(m+1)Binomial[3, m]m^k, {m, 1, k}]
|
|
PROG
|
(PARI) Vec(3*x*(1 - 9*x + 31*x^2 - 39*x^3 + 18*x^4) / ((1 - x)*(1 - 2*x)*(1 - 3*x)) + O(x^30)) \\ Colin Barker, May 21 2017
|
|
CROSSREFS
|
|
|
KEYWORD
|
sign,easy
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|