A325252 Number of integer partitions of n with frequency depth floor(sqrt(n)).

1, 1, 1, 1, 2, 1, 3, 1, 3, 8, 11, 11, 19, 17, 25, 29, 83, 113, 124, 171, 190, 242, 289, 368, 399, 796, 981, 1182, 1442, 1709, 2096, 2469, 2990, 3545, 4276, 5037, 8417, 10466, 12824, 15721, 19104, 23267, 27981, 33856, 40515, 48508, 57826, 68982, 81493, 446, 738

Offset

0,5

Comments

The adjusted frequency depth of an integer partition is 0 if the partition is empty, and otherwise it is 1 plus the number of times one must take the multiset of multiplicities to reach a singleton. For example, the partition (32211) has adjusted frequency depth 5 because we have: (32211) -> (221) -> (21) -> (11) -> (2).

Links

Table of n, a(n) for n=0..50.

Example

The a(2) = 1 through a(12) = 19 partitions (A = 10, B = 11):
  2  3  22    11111  33      1111111  44        54      64    65    75
        1111         222              2222      63      73    74    84
                     111111           11111111  72      82    83    93
                                                81      91    92    A2
                                                432     532   A1    B1
                                                531     541   542   543
                                                621     631   632   642
                                                222111  721   641   651
                                                        3322  731   732
                                                        4321  821   741
                                                        4411  5321  831
                                                                    921
                                                                    4422
                                                                    5421
                                                                    5511
                                                                    6321
                                                                    332211
                                                                    333111
                                                                    22221111

Mathematica

fdadj[ptn_List]:=If[ptn=={}, 0, Length[NestWhileList[Sort[Length/@Split[#1]]&, ptn, Length[#1]>1&]]];
Table[Length[Select[IntegerPartitions[n], fdadj[#]==Floor[Sqrt[n]]&]], {n, 0, 30}]

Crossrefs

Cf. A117571, A181819, A225485, A323014, A323023, A325245, A325246, A325253, A325258, A325271, A325278, A325280, A325282.

Sequence in context: A213594 A335105 A350597 * A243334 A355531 A234809

Adjacent sequences: A325249 A325250 A325251 * A325253 A325254 A325255

Keyword

nonn

Author

Gus Wiseman, Apr 22 2019

Status

approved