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Revision History for A237821 (Underlined text is an addition; strikethrough text is a deletion.)

Showing entries 1-10 | older changes
A237821 Number of partitions of n such that 2*(least part) <= greatest part.
(history; published version)
#14 by Michael De Vlieger at Sat May 27 10:33:02 EDT 2023
STATUS

proposed

approved

#13 by Seiichi Manyama at Sat May 27 10:16:21 EDT 2023
STATUS

editing

proposed

#12 by Seiichi Manyama at Sat May 27 09:55:25 EDT 2023
FORMULA

G.f.: sum{Sum_{i>=1} sum{Sum_{j>=0} x^(3*i+j)/prod() /Product_{k=i, ..2*i+j, } (1-x^k))). - _Seiichi Manyama_, May 27 2023

#11 by Seiichi Manyama at Sat May 27 09:54:11 EDT 2023
FORMULA

G.f.: sum{i>=1} sum{j>=0} x^(3*i+j)/prod(k=i, 2*i+j, 1-x^k))

STATUS

approved

editing

#10 by Michael De Vlieger at Thu May 18 11:54:03 EDT 2023
STATUS

proposed

approved

#9 by Gus Wiseman at Wed May 17 23:26:28 EDT 2023
STATUS

editing

proposed

#8 by Gus Wiseman at Mon May 15 22:12:18 EDT 2023
CROSSREFS

For > < instead of <= we have A237820, ranks A362982.

For <= >= instead of >= <= we have A237824, ranks A362981.

#7 by Gus Wiseman at Mon May 15 22:08:10 EDT 2023
EXAMPLE

(21) (31) (41) (42) (52) (62)

(211) (221) (51) (61) (71)

(311) (321) (331) (422)

(2111) (411) (421) (431)

(2211) (511) (521)

(3111) (2221) (611)

(21111) (3211) (3221)

(4111) (3311)

(22111) (4211)

(31111) (5111)

(211111) (22211)

(32111)

(41111)

(221111)

(311111)

(2111111)

(21) (31) (32) (42) (43) (53)

(211) (41) (51) (52) (62)

(311) (321) (61) (71)

(2111) (411) (322) (422)

(2211) (421) (431)

(3111) (511) (521)

(21111) (3211) (611)

(4111) (3221)

(22111) (3311)

(31111) (4211)

(211111) (5111)

(32111)

(41111)

(221111)

(311111)

(2111111)

CROSSREFS

Cf. A237820.

The conjugate partitions have ranks A362980.

Cf. A002865 ptns_no1, A008284 tri_ptns, A171979 ptns_max_is_mode, A237984 ptns_mean_is_part, A238478 ptns_unq_medn, A238479 ptns_not_unq_medn, A327472 ptns_wo_mean, A359893 tri_ptns_by_medn_half, A362612 ptns_max_is_only_mode, A362622 prix_max_in_mid, A362980 prix_medn_neq_max.

Cf. A002865, A008284, A171979, A237984, A238478, A238479, A327472, A359893, A362612, A362622.

#6 by Gus Wiseman at Mon May 15 22:03:11 EDT 2023
COMMENTS

By conjugation, also the number of integer partitions of n with different median from maximum, ranks A362980. - Gus Wiseman, May 15 2023

EXAMPLE

From Gus Wiseman, May 15 2023: (Start)

The a(3) = 1 through a(8) = 16 partitions wirth 2*(least part) <= greatest part:

(21) (31) (41) (42) (52) (62)

(211) (221) (51) (61) (71)

(311) (321) (331) (422)

(2111) (411) (421) (431)

(2211) (511) (521)

(3111) (2221) (611)

(21111) (3211) (3221)

(4111) (3311)

(22111) (4211)

(31111) (5111)

(211111) (22211)

(32111)

(41111)

(221111)

(311111)

(2111111)

The a(3) = 1 through a(8) = 16 partitions with different median from maximum:

(21) (31) (32) (42) (43) (53)

(211) (41) (51) (52) (62)

(311) (321) (61) (71)

(2111) (411) (322) (422)

(2211) (421) (431)

(3111) (511) (521)

(21111) (3211) (611)

(4111) (3221)

(22111) (3311)

(31111) (4211)

(211111) (5111)

(32111)

(41111)

(221111)

(311111)

(2111111)

(End)

CROSSREFS

The complement is counted by A053263, ranks A081306.

These partitions have ranks A069900.

The case of equality is A118096.

For > instead of <= we have A237820, ranks A362982.

For <= instead of >= we have A237824, ranks A362981.

A000041 counts integer partitions, strict A000009.

A325347 counts partitions with integer median, complement A307683.

Cf. A002865 ptns_no1, A008284 tri_ptns, A171979 ptns_max_is_mode, A237984 ptns_mean_is_part, A238478 ptns_unq_medn, A238479 ptns_not_unq_medn, A327472 ptns_wo_mean, A359893 tri_ptns_by_medn_half, A362612 ptns_max_is_only_mode, A362622 prix_max_in_mid, A362980 prix_medn_neq_max.

STATUS

approved

editing

#5 by Michel Marcus at Tue Feb 18 13:05:20 EST 2014
STATUS

reviewed

approved

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Last modified August 30 17:27 EDT 2024. Contains 375545 sequences. (Running on oeis4.)