A367224 Numbers m with a divisor whose prime indices sum to bigomega(m).
1, 2, 4, 6, 8, 9, 12, 15, 16, 18, 20, 21, 24, 30, 32, 33, 36, 39, 40, 42, 45, 48, 50, 51, 54, 56, 57, 60, 64, 66, 69, 70, 72, 75, 78, 80, 81, 84, 87, 90, 93, 96, 100, 102, 105, 108, 110, 111, 112, 114, 120, 123, 125, 126, 128, 129, 130, 132, 135, 138, 140, 141
Offset: 1
Keywords
Examples
The prime indices of 24 are {1,1,1,2} with submultiset {1,1,2} summing to 4, so 24 is in the sequence. The terms together with their prime indices begin: 1: {} 2: {1} 4: {1,1} 6: {1,2} 8: {1,1,1} 9: {2,2} 12: {1,1,2} 15: {2,3} 16: {1,1,1,1} 18: {1,2,2} 20: {1,1,3} 21: {2,4} 24: {1,1,1,2} 30: {1,2,3} 32: {1,1,1,1,1}
Crossrefs
The following sequences count and rank integer partitions and finite sets according to whether their length is a subset-sum or linear combination of the parts. The current sequence is starred.
sum-full sum-free comb-full comb-free
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Triangles:
Programs
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Mathematica
prix[n_]:=If[n==1, {}, Flatten[Cases[FactorInteger[n], {p_,k_}:>Table[PrimePi[p], {k}]]]]; Select[Range[100], MemberQ[Total/@prix/@Divisors[#], PrimeOmega[#]]&]
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