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A318589 Heinz numbers of integer partitions whose sum of reciprocals squared is the reciprocal of an integer. 5
2, 3, 5, 7, 9, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 49, 53, 59, 61, 67, 71, 73, 79, 81, 83, 89, 97, 101, 103, 107, 109, 113, 125, 127, 131, 137, 139, 149, 151, 157, 163, 167, 169, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251 (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..59.

MATHEMATICA

Select[Range[2, 1000], IntegerQ[1/Total[If[#==1, {}, Cases[FactorInteger[#], {p_, k_}:>k/PrimePi[p]^2]]]]&]

CROSSREFS

Cf. A001222, A051908, A056239, A058360, A112798, A289506, A289507, A316854, A316855.

Cf. A318584, A318585, A318586, A318587, A318588.

Sequence in context: A095415 A301987 A316857 * A132630 A033946 A189710

Adjacent sequences:  A318586 A318587 A318588 * A318590 A318591 A318592

KEYWORD

nonn

AUTHOR

Gus Wiseman, Aug 29 2018

STATUS

approved

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Last modified May 21 15:32 EDT 2019. Contains 323444 sequences. (Running on oeis4.)