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.

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A325719 Number of separable partitions of n in which the number of distinct (repeatable) parts is > 4.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 5, 10, 20, 35, 57, 93, 144, 217, 317, 455, 635, 890, 1202, 1623, 2148, 2837, 3673, 4768, 6082, 7740, 9753, 12262, 15253, 18972, 23373, 28759, 35143, 42867, 51998, 62967, 75865, 91243, 109315, 130701, 155752
Offset: 1

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Author

Clark Kimberling, May 19 2019

Keywords

Comments

A partition is separable if there is an ordering of its parts in which no consecutive parts are identical. See A325534 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    (separable=Table[Map[#[[1]]&,Select[Map[{#,Quotient[(1+Length[#]),Max[Map[Length,Split[#]]]]}&,IntegerPartitions[nn]],#[[2]]>1&]],{nn,35}]);
    Map[Length[Select[Map[{#,Length[Union[#]]}&,#],#[[2]]>4&]]&,separable]
    (* Peter J. C. Moses, May 08 2019 *)

Formula

a(n) = A325534(n) - A325713(n) for n >= 1.
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