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A024176
a(n) = (n+2)!(1/3 - 1/4 + ... + c/(n+2)), where c=(-1)^(n+1).
2
2, 2, 34, 84, 1308, 5424, 89136, 528480, 9442080, 73388160, 1433047680, 13835646720, 294712992000, 3407733504000, 78854259456000, 1063689242112000, 26612469305856000, 410604285708288000, 11055592008050688000, 192132082005405696000, 5543038613901938688000
OFFSET
1,1
LINKS
FORMULA
a(n) = 2*A024188(n).
a(n) ~ sqrt(2*Pi) * (log(2) - 1/2) * n^(n + 5/2) / exp(n). - Vaclav Kotesovec, Jan 02 2020
MATHEMATICA
Table[(n+2)! * Sum[(-1)^(k+1)/k, {k, 3, n+2}], {n, 1, 25}] (* Vaclav Kotesovec, Jan 02 2020 *)
PROG
(PARI) a(n) = (n+2)!*sum(x=1, n, (-1)^(x+1)/(x+2)); \\ Michel Marcus, Mar 21 2013
CROSSREFS
Cf. A024188.
Sequence in context: A018976 A074127 A297795 * A349033 A334470 A286375
KEYWORD
nonn
EXTENSIONS
Terms a(13) and beyond from Andrew Howroyd, Jan 01 2020
STATUS
approved