cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A360070 Numbers for which there exists an integer partition such that the parts have the same mean as the multiplicities.

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%I A360070 #18 Jan 29 2023 21:02:11
%S A360070 1,4,8,9,12,16,18,20,25,27,32,36,45,48,49,50,54,63,64,72,75,80,81,90,
%T A360070 96,98,99,100,108,112,117,121,125,128,144,147,150,160,162,169,175,176,
%U A360070 180,192,196,200,208,216,224,225,240,242,243,245,250,252,256,272
%N A360070 Numbers for which there exists an integer partition such that the parts have the same mean as the multiplicities.
%C A360070 Conjecture: No term > 1 is squarefree.
%e A360070 A partition of 20 with the same mean as its multiplicities is (5,4,3,2,1,1,1,1,1,1), so 20 is in the sequence.
%t A360070 Select[Range[30],Select[IntegerPartitions[#],Mean[#]==Mean[Length/@Split[#]]&]!={}&]
%Y A360070 Positions of positive terms in A360068, ranked by A359903.
%Y A360070 A000041 counts partitions, strict A000009.
%Y A360070 A058398 counts partitions by mean, see also A008284, A327482.
%Y A360070 A088529/A088530 gives mean of prime signature (A124010).
%Y A360070 A326567/A326568 gives mean of prime indices (A112798).
%Y A360070 Cf. A005117, A067340, A067538, A240219, A316313, A349156, A359904, A359905, A360069.
%K A360070 nonn
%O A360070 1,2
%A A360070 _Gus Wiseman_, Jan 27 2023
%E A360070 a(22)-a(58) from _Alois P. Heinz_, Jan 29 2023