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Revision History for A332741

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Number of unimodal negated permutations of a multiset whose multiplicities are the prime indices of n.
(history; published version)
#8 by Susanna Cuyler at Mon Mar 09 18:26:26 EDT 2020
STATUS

proposed

approved

#7 by Gus Wiseman at Mon Mar 09 15:24:16 EDT 2020
STATUS

editing

proposed

#6 by Gus Wiseman at Mon Mar 09 08:53:35 EDT 2020
CROSSREFS

Heinz numbers of partitions Numbers with non-unimodal negated run-lengths prime signature are A332642.

#5 by Gus Wiseman at Mon Mar 09 08:40:10 EDT 2020
CROSSREFS

Heinz numbers of partitions with non-unimodal negated run-lengths are A332642.

#4 by Gus Wiseman at Mon Mar 09 08:33:51 EDT 2020
CROSSREFS

Partitions whose 0-appended first differences with zero appended are unimodal are A332283.

#3 by Gus Wiseman at Mon Mar 09 08:33:24 EDT 2020
NAME

allocated for Gus WisemanNumber of unimodal negated permutations of a multiset whose multiplicities are the prime indices of n.

DATA

1, 1, 1, 2, 1, 2, 1, 4, 3, 2, 1, 4, 1, 2, 3, 8, 1, 6, 1, 4, 3, 2, 1, 8, 4, 2, 9, 4, 1, 6, 1, 16, 3, 2, 4, 12, 1, 2, 3, 8, 1, 6, 1, 4, 9, 2, 1, 16, 5, 8, 3, 4, 1, 18, 4, 8, 3, 2, 1, 12, 1, 2, 9, 32, 4, 6, 1, 4, 3, 8, 1, 24, 1, 2, 12, 4, 5, 6, 1, 16, 27, 2, 1

OFFSET

1,4

COMMENTS

This multiset is generally not the same as the multiset of prime indices of n. For example, the prime indices of 12 are {1,1,2}, while a multiset whose multiplicities are {1,1,2} is {1,1,2,3}.

A sequence of positive integers is unimodal if it is the concatenation of a weakly increasing and a weakly decreasing sequence.

LINKS

Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/UnimodalSequence.html">Unimodal Sequence</a>

FORMULA

a(n) + A332742(n) = A318762(n).

EXAMPLE

The a(12) = 4 permutations:

{1,1,2,3}

{2,1,1,3}

{3,1,1,2}

{3,2,1,1}

MATHEMATICA

nrmptn[n_]:=Join@@MapIndexed[Table[#2[[1]], {#1}]&, If[n==1, {}, Flatten[Cases[FactorInteger[n]//Reverse, {p_, k_}:>Table[PrimePi[p], {k}]]]]];

unimodQ[q_]:=Or[Length[q]<=1, If[q[[1]]<=q[[2]], unimodQ[Rest[q]], OrderedQ[Reverse[q]]]];

Table[Length[Select[Permutations[nrmptn[n]], unimodQ[-#]&]], {n, 30}]

CROSSREFS

Dominated by A318762.

The non-negated version is A332294.

The complement is counted by A332742.

A less interesting version is A333145.

Unimodal compositions are A001523.

Unimodal normal sequences are A007052.

Heinz numbers of partitions with unimodal negated run-lengths are A332642.

Partitions whose first differences with zero appended are unimodal are A332283.

Compositions whose negation is unimodal are A332578.

Partitions with unimodal negated run-lengths are A332638.

Cf. A056239, A112798, A115981, A124010, A181819, A181821, A304660, A332280, A332288, A332639, A332669, A332672.

KEYWORD

allocated

nonn

AUTHOR

Gus Wiseman, Mar 09 2020

STATUS

approved

editing

#2 by Gus Wiseman at Fri Feb 21 21:12:41 EST 2020
KEYWORD

allocating

allocated

#1 by Gus Wiseman at Fri Feb 21 21:12:41 EST 2020
NAME

allocated for Gus Wiseman

KEYWORD

allocating

STATUS

approved