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A318586 Number of integer partitions of n whose sum of reciprocals squared is the reciprocal of an integer. 6

%I #10 Sep 03 2018 23:05:15

%S 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,

%T 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,

%U 12,18,6,11,14,22,9,24,11,21,22,25,24,23,28,32

%N Number of integer partitions of n whose sum of reciprocals squared is the reciprocal of an integer.

%H Giovanni Resta, <a href="/A318586/b318586.txt">Table of n, a(n) for n = 1..150</a>

%e The a(42) = 9 integer partitions:

%e (42)

%e (21,14,7)

%e (18,9,9,6)

%e (18,9,9,3,3)

%e (20,10,4,4,4)

%e (12,12,12,4,2)

%e (10,5,5,5,5,5,5,2)

%e (12,6,6,4,4,4,2,2,2)

%e (6,6,4,4,4,4,3,3,3,3,2)

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

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

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

%K nonn

%O 1,4

%A _Gus Wiseman_, Aug 29 2018

%E a(61)-a(80) from _Giovanni Resta_, Sep 03 2018

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Last modified April 23 13:11 EDT 2024. Contains 371913 sequences. (Running on oeis4.)