A324761 - OEIS

A324761

Heinz numbers of integer partitions not containing 1 or any prime indices of the parts.

1, 3, 5, 7, 9, 11, 13, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 41, 43, 47, 49, 51, 53, 57, 59, 61, 63, 65, 67, 71, 73, 77, 79, 81, 83, 85, 87, 89, 91, 93, 95, 97, 99, 101, 103, 107, 109, 113, 115, 121, 123, 125, 127, 129, 131, 133, 137, 139, 143, 147, 149

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OFFSET

1,2

COMMENTS

A prime index of n is a number m such that prime(m) divides n. The multiset of prime indices of n is row n of A112798. The Heinz number of an integer partition (y_1, ..., y_k) is prime(y_1) * ... * prime(y_k).

LINKS

Table of n, a(n) for n=1..62.

EXAMPLE

The sequence of terms together with their prime indices begins:

1: {}

3: {2}

5: {3}

7: {4}

9: {2,2}

11: {5}

13: {6}

17: {7}

19: {8}

21: {2,4}

23: {9}

25: {3,3}

27: {2,2,2}

29: {10}

31: {11}

33: {2,5}

35: {3,4}

37: {12}

41: {13}

43: {14}

MATHEMATICA

primeMS[n_]:=If[n==1, {}, Flatten[Cases[FactorInteger[n], {p_, k_}:>Table[PrimePi[p], {k}]]]];

Select[Range[1, 100, 2], Intersection[primeMS[#], Union@@primeMS/@primeMS[#]]=={}&]

CROSSREFS

The subset version is A324742, with maximal case A324763. The strict integer partition version is A324752. The integer partition version is A324757. An infinite version is A324695.

Cf. A000720, A001221, A007097, A056239, A112798, A276625, A289509, A290822, A304360, A306844, A324743, A324751, A324756, A324758, A324764.

Sequence in context: A084820 A324846 A324760 * A356171 A244579 A151991

Adjacent sequences: A324758 A324759 A324760 * A324762 A324763 A324764

KEYWORD

nonn

AUTHOR

Gus Wiseman, Mar 17 2019

STATUS

approved