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A317245
Number of supernormal integer partitions of n.
27
1, 1, 1, 2, 2, 2, 2, 2, 2, 3, 4, 4, 1, 3, 3, 4, 2, 4, 5, 6, 6, 10, 7, 10, 9, 9, 10, 11, 12, 12, 21, 12, 18, 17, 21, 19, 28, 23, 28, 26, 27, 24, 32, 29, 36, 34, 46, 42, 55, 48, 65, 65, 74, 70, 88, 81, 83, 103, 112, 129, 153, 157, 190, 205, 210, 242, 283, 276, 321
OFFSET
0,4
COMMENTS
An integer partition is supernormal if either (1) it is of the form 1^n for some n >= 0, or (2a) it spans an initial interval of positive integers, and (2b) its multiplicities, sorted in weakly decreasing order, are themselves a supernormal integer partition.
EXAMPLE
The a(10) = 4 supernormal integer partitions are (4321), (33211), (322111), (1111111111).
The a(21) = 10 supernormal integer partitions:
(654321),
(4443321),
(44432211), (44333211), (44332221),
(4432221111), (4333221111), (4332222111),
(433322211),
(111111111111111111111).
MATHEMATICA
supnrm[q_]:=Or[q=={}||Union[q]=={1}, And[Union[q]==Range[Max[q]], supnrm[Sort[Length/@Split[q], Greater]]]];
Table[Length[Select[IntegerPartitions[n], supnrm]], {n, 0, 30}]
KEYWORD
nonn
AUTHOR
Gus Wiseman, Jul 24 2018
STATUS
approved