A212887 a(n) is the prime p corresponding to the smallest integer k such that k^2 == p (mod prime(n)).

2, 5, 3, 2, 17, 2, 7, 5, 7, 23, 41, 2, 11, 5, 3, 59, 29, 71, 2, 17, 11, 3, 43, 41, 37, 7, 31, 17, 13, 7, 5, 47, 59, 47, 151, 2, 23, 17, 79, 5, 3, 59, 2, 113, 2, 29, 71, 23, 17, 83, 5, 67, 61, 131, 53, 47, 43, 41, 31, 17, 13, 11, 7, 67, 239, 53, 227, 47, 2, 107

Offset

4,1

Comments

The corresponding values of k are {3, 4, 4, 6, 6, 5, 6, 6, 9, 8, 16, 7, 8, 8, 8, 27, …}

Links

Michel Lagneau, Table of n, a(n) for n = 4..10000

Example

a(8) = 17 because 17 == 6^2 mod 19 where 19 = prime(8) and 6 is the smallest k.
Remark : 11 == 7^2 mod 19, but 7 > 6.

Maple

for n from 2 to 100 do:p:=ithprime(n):i:=0:for k from 0 to p-1 while(i=0) do: q:=irem(k^2, p):if type(q, prime)=true then i:=1:printf(`%d, `, q):else fi:od:od:

Crossrefs

Cf. A000224, A095972.

Sequence in context: A195784 A279623 A287040 * A163766 A004200 A069998

Adjacent sequences: A212884 A212885 A212886 * A212888 A212889 A212890

Keyword

nonn

Author

Michel Lagneau, May 29 2012

Status

approved