A347462 Number of distinct possible reverse-alternating products of integer partitions of n.

1, 1, 2, 3, 4, 6, 8, 11, 13, 17, 22, 28, 33, 42, 51, 59, 69, 84, 100, 117, 137, 163, 191, 222, 256, 290, 332, 378, 429, 489, 564, 643, 729, 819, 929, 1040, 1167, 1313, 1473, 1647, 1845, 2045, 2272, 2521, 2785, 3076, 3398, 3744, 4115, 4548, 5010, 5524, 6086

Offset

0,3

Comments

We define the alternating product of a sequence (y_1,...,y_k) to be Product_i y_i^((-1)^(i-1)). The reverse-alternating product is the alternating product of the reversed sequence.

Links

Table of n, a(n) for n=0..52.

Example

Partitions representing each of the a(7) = 11 reverse-alternating products:
     (7) -> 7
    (61) -> 1/6
    (52) -> 2/5
   (511) -> 5
    (43) -> 3/4
   (421) -> 2
  (4111) -> 1/4
   (331) -> 1
   (322) -> 3
  (3211) -> 2/3
  (2221) -> 1/2

Mathematica

revaltprod[q_]:=Product[Reverse[q][[i]]^(-1)^(i-1), {i, Length[q]}];
Table[Length[Union[revaltprod/@IntegerPartitions[n]]], {n, 0, 30}]

Crossrefs

The version for non-reverse alternating sum instead of product is A004526.

Counting only integers gives A028310, non-reverse A347707.

The version for factorizations is A038548, non-reverse A347460.

The non-reverse version is A347461.

A000041 counts partitions.

A027187 counts partitions of even length.

A027193 counts partitions of odd length.

A103919 counts partitions by sum and alternating sum (reverse: A344612).

A108917 counts knapsack partitions, ranked by A299702.

A122768 counts distinct submultisets of partitions.

A126796 counts complete partitions.

A293627 counts knapsack factorizations by sum.

A301957 counts distinct subset-products of prime indices.

A304792 counts subset-sums of partitions, positive A276024, strict A284640.

A304793 counts distinct positive subset-sums of prime indices.

A325534 counts separable partitions, ranked by A335433.

A325535 counts inseparable partitions, ranked by A335448.

Cf. A000070, A001055, A002033, A002219, A028983, A119620, A325768, A345926, A347443, A347444, A347445, A347446.

Sequence in context: A211522 A368482 A105799 * A340589 A102463 A242110

Adjacent sequences: A347459 A347460 A347461 * A347463 A347464 A347465

Keyword

nonn

Author

Gus Wiseman, Oct 06 2021

Status

approved