A085641 Smallest prime == 1 (mod p*q*...*k) where p, q, ..., k are all the distinct prime divisors of n. Or, smallest prime == 1 (mod the largest squarefree divisor of n).

2, 3, 7, 3, 11, 7, 29, 3, 7, 11, 23, 7, 53, 29, 31, 3, 103, 7, 191, 11, 43, 23, 47, 7, 11, 53, 7, 29, 59, 31, 311, 3, 67, 103, 71, 7, 149, 191, 79, 11, 83, 43, 173, 23, 31, 47, 283, 7, 29, 11, 103, 53, 107, 7, 331, 29, 229, 59, 709, 31, 367, 311, 43, 3, 131, 67, 269, 103, 139

Offset

1,1

Comments

All the numbers having the same set of prime divisors are mapped to the same prime.

Links

Andrew Howroyd, Table of n, a(n) for n = 1..10000

Formula

a(n) = A034694(A007947(n)).

Prog

(PARI) a(n)={my(m=vecprod(factor(n)[, 1]), p=1); while(!isprime(p), p+=m); p} \\ Andrew Howroyd, Dec 10 2024

Crossrefs

Cf. A007947, A034694.

Sequence in context: A160727 A187152 A086508 * A086516 A281962 A358415

Adjacent sequences: A085638 A085639 A085640 * A085642 A085643 A085644

Keyword

easy,nonn,changed

Author

Amarnath Murthy, Jason Earls, Jul 11 2003

Extensions

Offset corrected by Andrew Howroyd, Dec 10 2024

Status

approved