|
| |
|
|
A370605
|
|
a(n) = n! * Sum_{d|n} 1/((d-1)! * (n/d)!^d).
|
|
0
|
|
|
|
1, 3, 4, 11, 6, 72, 8, 499, 850, 4988, 12, 142232, 14, 949392, 7385394, 26739587, 18, 1462302432, 20, 21233776156, 253684768502, 151243121780, 24, 104533367794192, 25973364296906, 102776106948752, 26798029481115778, 95394359150584904, 30
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,2
|
|
|
LINKS
|
|
|
|
FORMULA
|
If p is prime, a(p) = 1 + p.
E.g.f.: Sum_{k>0} x^k/k! * exp(x^k/k!).
|
|
|
PROG
|
(PARI) a(n) = n!*sumdiv(n, d, 1/((d-1)!*(n/d)!^d));
(PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(sum(k=1, N, x^k/k!*exp(x^k/k!))))
|
|
|
CROSSREFS
|
|
|
|
KEYWORD
|
nonn
|
|
|
AUTHOR
|
|
|
|
STATUS
|
approved
|
| |
|
|
