A327389 Maximum divisor of n that is prime or whose prime indices are pairwise coprime.

1, 2, 3, 4, 5, 6, 7, 8, 3, 10, 11, 12, 13, 14, 15, 16, 17, 6, 19, 20, 7, 22, 23, 24, 5, 26, 3, 28, 29, 30, 31, 32, 33, 34, 35, 12, 37, 38, 13, 40, 41, 14, 43, 44, 15, 46, 47, 48, 7, 10, 51, 52, 53, 6, 55, 56, 19, 58, 59, 60, 61, 62, 7, 64, 13, 66, 67, 68, 69

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.

Links

Table of n, a(n) for n=1..69.

Gus Wiseman, Sequences counting and encoding certain classes of multisets

Formula

If n is in A302569, then a(n) = n.

Mathematica

primeMS[n_]:=If[n==1, {}, Flatten[Cases[FactorInteger[n], {p_, k_}:>Table[PrimePi[p], {k}]]]];
Table[Max[Select[Divisors[n], UnsameQ@@Sort[Join@@Union/@primeMS/@primeMS[#]]&]], {n, 100}]

Crossrefs

See link for additional cross-references.

Cf. A000005, A000837, A006530, A056239, A112798, A327398.

Sequence in context: A279649 A278060 A160597 * A282779 A327535 A305902

Adjacent sequences: A327386 A327387 A327388 * A327390 A327391 A327392

Keyword

nonn

Author

Gus Wiseman, Sep 15 2019

Status

approved