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A318586 Number of integer partitions of n whose sum of reciprocals squared is the reciprocal of an integer. 6
1, 1, 1, 2, 1, 1, 1, 3, 2, 1, 1, 3, 1, 2, 3, 3, 1, 4, 1, 3, 1, 2, 1, 5, 2, 1, 4, 5, 1, 5, 1, 6, 3, 2, 4, 8, 2, 4, 2, 6, 3, 9, 2, 4, 7, 5, 4, 11, 8, 7, 8, 9, 5, 12, 5, 16, 5, 10, 5, 25, 10, 9, 13, 18, 12, 18, 6, 11, 14, 22, 9, 24, 11, 21, 22, 25, 24, 23, 28, 32 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Giovanni Resta, Table of n, a(n) for n = 1..150

EXAMPLE

The a(42) = 9 integer partitions:

  (42)

  (21,14,7)

  (18,9,9,6)

  (18,9,9,3,3)

  (20,10,4,4,4)

  (12,12,12,4,2)

  (10,5,5,5,5,5,5,2)

  (12,6,6,4,4,4,2,2,2)

  (6,6,4,4,4,4,3,3,3,3,2)

MATHEMATICA

Table[Length[Select[IntegerPartitions[n], IntegerQ[1/Total[#^(-2)]]&]], {n, 30}]

CROSSREFS

Cf. A000041, A051908, A058360, A289506, A289507, A316854, A316857.

Cf. A318584, A318585, A318587, A318588, A318589.

Sequence in context: A136565 A181591 A325939 * A222580 A316978 A331023

Adjacent sequences:  A318583 A318584 A318585 * A318587 A318588 A318589

KEYWORD

nonn

AUTHOR

Gus Wiseman, Aug 29 2018

EXTENSIONS

a(61)-a(80) from Giovanni Resta, Sep 03 2018

STATUS

approved

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Last modified February 20 17:04 EST 2020. Contains 332080 sequences. (Running on oeis4.)