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A327529
Maximum divisor of n that is 1 or whose prime indices are relatively prime.
3
1, 2, 1, 4, 1, 6, 1, 8, 1, 10, 1, 12, 1, 14, 15, 16, 1, 18, 1, 20, 1, 22, 1, 24, 1, 26, 1, 28, 1, 30, 1, 32, 33, 34, 35, 36, 1, 38, 1, 40, 1, 42, 1, 44, 45, 46, 1, 48, 1, 50, 51, 52, 1, 54, 55, 56, 1, 58, 1, 60, 1, 62, 1, 64, 1, 66, 1, 68, 69, 70, 1, 72, 1, 74
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. Numbers whose prime indices are relatively prime are A289509. The number of divisors of n that are 1 or whose prime indices are relatively prime is A327530(n).
FORMULA
a(n) = n if n is in A289509, otherwise a(n) = 1.
MAPLE
g:= proc(n) uses numtheory; igcd(op(map(pi, factorset(n))))=1 end proc:
seq(`if`(g(n), n, 1), n=1..100); # Robert Israel, Sep 19 2019
MATHEMATICA
Table[Max[Select[Divisors[n], #==1||GCD@@PrimePi/@First/@FactorInteger[#]==1&]], {n, 100}]
CROSSREFS
See link for additional cross-references.
Sequence in context: A009531 A124625 A327512 * A318775 A317500 A339420
KEYWORD
nonn
AUTHOR
Gus Wiseman, Sep 17 2019
STATUS
approved