|
|
A046673
|
|
a(n) = (2n)!*Sum_{i=1..n} 1/i.
|
|
6
|
|
|
2, 36, 1320, 84000, 8285760, 1173553920, 226040855040, 56865153945600, 18112111963545600, 7125892746964992000, 3394344333441245184000, 1925382105537337294848000, 1282520788685931213619200000, 991363455147400701817651200000, 880169729965718014490443776000000
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
LINKS
|
|
|
MATHEMATICA
|
Table[(2n)!HarmonicNumber[n], {n, 20}] (* Harvey P. Dale, Sep 27 2013 *)
|
|
PROG
|
(PARI) a(n) = (2*n)!*sum(k=1, n, 1/k); \\ Michel Marcus, Jul 11 2018
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|