

A292285


GCD of orders (in GF(p)) of primes dividing p1, for odd primes p.


2



2, 4, 3, 5, 3, 8, 18, 11, 7, 1, 18, 20, 2, 23, 13, 29, 10, 22, 5, 3, 39, 41, 11, 48, 25, 17, 53, 9, 14, 7, 65, 68, 46, 37, 5, 2, 162, 83, 43, 89, 15, 19, 16, 98, 11, 35, 37, 113, 19, 29, 119, 8, 25, 16, 131, 67, 3, 23, 10, 94, 73, 1, 155, 39, 79, 15, 7, 173, 174, 88, 179, 61, 62, 378, 191, 97, 11, 25, 51, 418, 35, 43, 9, 73, 17, 112, 38, 23, 77
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OFFSET

2,1


LINKS

Robert Israel, Table of n, a(n) for n = 2..10000
Seva, Posting on mathoverflow.net, October 29 2014.


EXAMPLE

For n = 14, the 14th prime is 43. The prime divisors of 42 are 2, 3, 7. The orders of 2, 3, 7, respectively, in GF(43), are 14,42,6, with GCD 2.


MAPLE

with(numtheory):
a:= n> (p> igcd(map(x> order(x, p), factorset(p1))[]))(ithprime(n)):
seq(a(n), n=2..100); # Alois P. Heinz, Dec 01 2017


CROSSREFS

Cf. A172058, A295975.
Sequence in context: A256751 A249484 A134017 * A163984 A283366 A048186
Adjacent sequences: A292282 A292283 A292284 * A292286 A292287 A292288


KEYWORD

nonn,look


AUTHOR

Jeffrey Shallit, Dec 01 2017


STATUS

approved



