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A335376
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Heinz numbers of totally co-strong integer partitions.
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3
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1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 51, 52, 53, 55, 56, 57, 58, 59, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71
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OFFSET
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1,2
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COMMENTS
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A sequence is totally co-strong if it is empty, equal to (1), or its run-lengths are weakly increasing (co-strong) and are themselves a totally co-strong sequence.
The Heinz number of an integer partition (y_1,...,y_k) is prime(y_1)*...*prime(y_k). This gives a bijective correspondence between positive integers and integer partitions.
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LINKS
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EXAMPLE
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The sequence of terms together with their prime indices begins:
1: {} 16: {1,1,1,1} 32: {1,1,1,1,1}
2: {1} 17: {7} 33: {2,5}
3: {2} 19: {8} 34: {1,7}
4: {1,1} 20: {1,1,3} 35: {3,4}
5: {3} 21: {2,4} 36: {1,1,2,2}
6: {1,2} 22: {1,5} 37: {12}
7: {4} 23: {9} 38: {1,8}
8: {1,1,1} 24: {1,1,1,2} 39: {2,6}
9: {2,2} 25: {3,3} 40: {1,1,1,3}
10: {1,3} 26: {1,6} 41: {13}
11: {5} 27: {2,2,2} 42: {1,2,4}
12: {1,1,2} 28: {1,1,4} 43: {14}
13: {6} 29: {10} 44: {1,1,5}
14: {1,4} 30: {1,2,3} 45: {2,2,3}
15: {2,3} 31: {11} 46: {1,9}
For example, 180 is the Heinz number of (3,2,2,1,1) which has run-lengths: (1,2,2) -> (1,2) -> (1,1) -> (2) -> (1). All of these are weakly increasing, so 180 is in the sequence.
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MATHEMATICA
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primeMS[n_]:=If[n==1, {}, Flatten[Cases[FactorInteger[n], {p_, k_}:>Table[PrimePi[p], {k}]]]];
totcostrQ[q_]:=Or[Length[q]<=1, And[OrderedQ[Length/@Split[q]], totcostrQ[Length/@Split[q]]]];
Select[Range[100], totcostrQ[Reverse[primeMS[#]]]&]
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CROSSREFS
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Partitions with weakly increasing run-lengths are A100883.
Totally strong partitions are counted by A316496.
The version for reversed partitions is (also) A316529.
These partitions are counted by A332275.
The widely normal version is A332293.
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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