The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A123636

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A123636

a(n) = 1 + 1*n + 1*n*2 + 1*n*2*(n-1) + 1*n*2*(n-1)*3 + 1*n*2*(n-1)*3*(n-2) + ... + n!.
(history; published version)

#13 by Hugo Pfoertner at Tue Sep 17 04:42:49 EDT 2024

STATUS

editing

approved

#12 by Hugo Pfoertner at Tue Sep 17 04:42:17 EDT 2024

DATA

1, 1, 3, 10, 37, 176, 979, 6658, 50873, 451180, 4376911, 47740694, 560586613, 7248848608, 99837660875, 1492197903466, 23571796088689, 399706304138708, 7121101849585543, 135049981967575870, 2678257990821099821, 56164666081871350984, 1226908363217557264003, 28188326528878836076178

STATUS

reviewed

editing

Discussion

Tue Sep 17

04:42

Hugo Pfoertner: Usual length of DATA.

#11 by Joerg Arndt at Tue Sep 17 04:01:40 EDT 2024

STATUS

proposed

reviewed

#10 by Jason Yuen at Mon Sep 16 23:10:02 EDT 2024

STATUS

editing

proposed

#9 by Jason Yuen at Mon Sep 16 23:04:10 EDT 2024

FORMULA

a(n) = 1 + Sum_{k=12..n} (floor((k + 1)/2)! * n!)/((n - floor(k/2))!) ). - G. C. Greubel, Oct 26 2017

STATUS

approved

editing

#8 by Vaclav Kotesovec at Fri Oct 09 03:00:38 EDT 2020

STATUS

editing

approved

#7 by Vaclav Kotesovec at Fri Oct 09 03:00:35 EDT 2020

FORMULA

a(n) ~ n!. - Vaclav Kotesovec, Oct 09 2020

STATUS

approved

editing

#6 by Alois P. Heinz at Thu Oct 26 16:43:00 EDT 2017

STATUS

proposed

approved

#5 by G. C. Greubel at Thu Oct 26 16:05:54 EDT 2017

STATUS

editing

proposed

#4 by G. C. Greubel at Thu Oct 26 16:05:44 EDT 2017

LINKS

G. C. Greubel, <a href="/A123636/b123636.txt">Table of n, a(n) for n = 0..449</a>

FORMULA

a(n) = 1 + Sum_{k=1..n} (floor((k + 1)/2)! * n!)/((n - floor(k/2))!) ). - G. C. Greubel, Oct 26 2017

MATHEMATICA

Join[{1}, Table[Sum[(Floor[(k + 1)/2]! * n!)/((n - Floor[k/2])!), {k, 1, n}], {n, 1, 50}]] (* G. C. Greubel, Oct 26 2017 *)

STATUS

approved

editing