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A327535
Maximum divisor of n that is 1, prime, or whose prime indices are relatively prime.
3
1, 2, 3, 4, 5, 6, 7, 8, 3, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 7, 22, 23, 24, 5, 26, 3, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 13, 40, 41, 42, 43, 44, 45, 46, 47, 48, 7, 50, 51, 52, 53, 54, 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. Numbers that are 1, prime, or whose prime indices are relatively prime are A327534. The number of divisors of n satisfying the same conditions is A327536(n).
FORMULA
If n is in A327534, then a(n) = n; otherwise a(n) = A006530(n).
EXAMPLE
The divisors of 63 that are 1, prime, or whose prime indices are relatively prime are {1, 3, 7}, so a(63) = 7.
MATHEMATICA
Table[Max@@Select[Divisors[n], #==1||PrimeQ[#]||GCD@@PrimePi/@First/@FactorInteger[#]==1&], {n, 100}]
CROSSREFS
See link for additional cross-references.
Sequence in context: A160597 A327389 A282779 * A305902 A245350 A307282
KEYWORD
nonn
AUTHOR
Gus Wiseman, Sep 17 2019
STATUS
approved