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.

A325765 Number of integer partitions of n with a unique consecutive subsequence summing to every positive integer from 1 to n.

Original entry on oeis.org

1, 1, 1, 2, 1, 3, 1, 3, 2, 3, 1, 5, 1, 3, 3, 4, 1, 5, 1, 5, 3, 3, 1, 7, 2, 3, 3, 5, 1, 7, 1, 5, 3, 3, 3, 8, 1, 3, 3, 7, 1, 7, 1, 5, 5, 3, 1, 9, 2, 5, 3
Offset: 0

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Author

Gus Wiseman, May 20 2019

Keywords

Comments

After a(0) = 1, same as A032741(n + 1) (number of proper divisors of n + 1).
The Heinz numbers of these partitions are given by A325764.

Examples

			The a(1) = 1 through a(13) = 3 partitions:
  (1)  (11)  (21)   (1111)  (221)    (111111)  (2221)     (3311)
             (111)          (311)              (4111)     (11111111)
                            (11111)            (1111111)
.
  (22221)      (1111111111)  (33311)        (111111111111)  (2222221)
  (51111)                    (44111)                        (7111111)
  (111111111)                (222221)                       (1111111111111)
                             (611111)
                             (11111111111)
		

Crossrefs

Programs

  • Mathematica
    normQ[m_]:=Or[m=={},Union[m]==Range[Max[m]]];
    Table[Length[Select[IntegerPartitions[n],normQ[Total/@Union[ReplaceList[#,{_,s__,_}:>{s}]]]&&UnsameQ@@Total/@Union[ReplaceList[#,{_,s__,_}:>{s}]]&]],{n,0,20}]