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A318587 Heinz numbers of integer partitions whose sum of reciprocals squared is 1. 5
2, 81, 8775, 64827, 950625, 1953125, 7022925, 9055935, 21781575, 36020025, 50124555, 51883209, 57909033, 102984375, 118978125, 760816875, 816747435, 981059625, 1206902781, 1265058675, 1387132263, 2359670625, 3902169375, 4868424351, 5222768733, 5430160125 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The Heinz number of an integer partition (y_1, ..., y_k) is prime(y_1) * ... * prime(y_k).

LINKS

Table of n, a(n) for n=1..26.

EXAMPLE

The sequence of integer partitions with Heinz numbers in this sequence begins: (1), (2222), (633222), (4444222), (66333322).

MATHEMATICA

Select[Range[100000], Total[If[#==1, {}, Cases[FactorInteger[#], {p_, k_}:>k/PrimePi[p]^2]]]==1&]

CROSSREFS

Cf. A001222, A051908, A056239, A112798, A289506, A289507, A316855, A316856, A316857.

Cf. A318584, A318585, A318586, A318588, A318589.

Sequence in context: A041799 A187858 A072408 * A302722 A123177 A209585

Adjacent sequences:  A318584 A318585 A318586 * A318588 A318589 A318590

KEYWORD

nonn

AUTHOR

Gus Wiseman, Aug 29 2018

EXTENSIONS

a(6)-a(26) from Alois P. Heinz, Aug 30 2018

STATUS

approved

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Last modified January 24 16:47 EST 2020. Contains 331209 sequences. (Running on oeis4.)