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Search: a367012 -id:a367012
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a(n) = Sum_{k=0..n} k! * k^(n-k).
+10
3
1, 1, 3, 11, 51, 287, 1899, 14447, 124251, 1192127, 12623979, 146250287, 1840024251, 24983863967, 364140992139, 5670546353807, 93960923507931, 1650688221777407, 30646388716777899, 599565840087487727, 12328458398407260411
OFFSET
0,3
LINKS
FORMULA
a(n) ~ Pi * n^(n+1) / exp(n).
a(n) ~ sqrt(Pi*n/2) * n!.
MATHEMATICA
Table[Sum[k! * k^(n-k), {k, 0, n}], {n, 1, 20}]
PROG
(PARI) a(n) = sum(k=0, n, k!*k^(n-k)); \\ Seiichi Manyama, Dec 31 2023
CROSSREFS
KEYWORD
nonn
AUTHOR
Vaclav Kotesovec, Nov 01 2023
EXTENSIONS
a(0)=1 prepended by Seiichi Manyama, Dec 31 2023
STATUS
approved
a(n) = Sum_{k=0..n} k! * k^k.
+10
0
1, 2, 10, 172, 6316, 381316, 33973636, 4184630356, 680641979476, 141267789027796, 36429267789027796, 11425158161234192596, 4282251538636575402196, 1890291840090813125264596, 970616058694975134467523796, 573593232413546537634467523796, 386530943604347679737893326531796
OFFSET
0,2
FORMULA
a(n) ~ n! * n^n. - Vaclav Kotesovec, Jan 13 2024
PROG
(PARI) a(n) = sum(k=0, n, k!*k^k);
CROSSREFS
Partial sums of A061711.
KEYWORD
nonn,easy
AUTHOR
Seiichi Manyama, Dec 31 2023
STATUS
approved

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