The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A137736 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A137736

Number of set partitions of [n*(n-1)/2].
(history; published version)

#17 by Alois P. Heinz at Wed Jul 24 09:47:16 EDT 2024

STATUS

editing

approved

#16 by Alois P. Heinz at Wed Jul 24 09:47:13 EDT 2024

CROSSREFS

Cf. A000110, A006125, A066655, A135084, A135085, A161680.

STATUS

approved

editing

#15 by Michael De Vlieger at Wed Jul 24 09:21:00 EDT 2024

STATUS

proposed

approved

#14 by Alois P. Heinz at Wed Jul 24 09:06:52 EDT 2024

STATUS

editing

proposed

#13 by Alois P. Heinz at Wed Jul 24 09:06:32 EDT 2024

COMMENTS

The number of set partitions of n(n-1)/2 is A137736(n)=sum(Stirling2((n^2-n)/2,k),k=0..(n^2-n)/2).

FORMULA

a(n) = Sum_{k=0..(n^2-n)/2} Stirling2((n^2-n)/2,k).

STATUS

proposed

editing

#12 by Alois P. Heinz at Wed Jul 24 08:03:10 EDT 2024

STATUS

editing

proposed

#11 by Alois P. Heinz at Wed Jul 24 08:02:18 EDT 2024

NAME

Number of set partitions of [n*(n-1)/2].

STATUS

proposed

editing

Discussion

Wed Jul 24

08:02

Alois P. Heinz: [n*(n-1)/2] = {1, 2, ..., n*(n-1)/2} ...

#10 by Alois P. Heinz at Wed Jul 24 08:00:44 EDT 2024

STATUS

editing

proposed

#9 by Alois P. Heinz at Wed Jul 24 07:59:39 EDT 2024

CROSSREFS

Cf. A006125, A066655, A135084, A135085, A161680.

#8 by Alois P. Heinz at Wed Jul 24 07:57:41 EDT 2024

MAPLE

for n from 1 to 10 do a(n):=bell((n^2-n)/2): print(a(n)); od:

seq(combinat[bell](n*(n-1)/2), n=0..12);

Discussion

Wed Jul 24

07:57

Alois P. Heinz: and program corrected ...