|
|
A111888
|
|
Eighth column of triangle A112492 (inverse scaled Pochhammer symbols).
|
|
2
|
|
|
|
OFFSET
|
0,2
|
|
COMMENTS
|
Also continuation of family of Differences of reciprocals of unity. See A001242, A111887 and triangle A008969.
|
|
LINKS
|
|
|
FORMULA
|
G.f.: 1/Product_{j=1..8} 1-8!*x/j.
a(n) = -((8!)^n) * Sum_{j=1..8} (-1)^j*binomial(8, j)/j^n, n>=0.
|
|
MATHEMATICA
|
T[n_, k_]:= T[n, k]= If[k==0 || k==n, 1, (k+1)^(n-k)*T[n-1, k-1] +k!*T[n-1, k]]; (* T = A112492 *)
|
|
PROG
|
(PARI) a(n) = -((8!)^n)*sum(j=1, 8, ((-1)^j)*binomial(8, j)/j^n); \\ Michel Marcus, Apr 28 2020
(Magma)
A111888:= func< n | (-1)*Factorial(8)^n*(&+[(-1)^j*Binomial(8, j)/j^n : j in [1..8]]) >;
(SageMath)
@CachedFunction
if (k==0 or k==n): return 1
else: return (k+1)^(n-k)*T(n-1, k-1) + factorial(k)*T(n-1, k)
|
|
CROSSREFS
|
Also right-hand column 7 in triangle A008969.
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|