A143427 a(n)=least prime == -1 mod 6 such that q(n)*(q(n)+a(n))-1 is prime with q(i)=i-th prime == 1 mod 6.

5, 5, 11, 11, 5, 5, 11, 23, 5, 11, 17, 41, 23, 5, 11, 17, 29, 17, 17, 11, 47, 41, 11, 11, 41, 11, 29, 41, 5, 11, 29, 17, 11, 5, 47, 17, 17, 53, 11, 5, 17, 17, 47, 29, 11, 23, 11, 5, 17, 5, 17, 29, 11, 17, 29, 11, 17, 5, 11, 17, 5, 17, 17, 29, 17, 17, 5, 23, 23, 11, 113, 17, 113, 5

Offset

1,1

Links

Pierre CAMI, Table of n, a(n) for n = 1..10000

Example

q(1)=7, 7*(7+5)-1=83 prime, 5 prime == -1 mod 6 so a(1)=5
q(2)=13, 13*(13+5)-1=233 prime, so a(2)=5
q(3)=19, 19*(19+5)-1=455 composite 19*(19+11)-1=569 prime, 11 prime == -1 mod 6 so a(3)=11

Crossrefs

Cf. A143428, A143429, A143430.

Sequence in context: A130889 A184827 A058610 * A287996 A239355 A218121

Adjacent sequences: A143424 A143425 A143426 * A143428 A143429 A143430

Keyword

nonn

Author

Pierre CAMI, Aug 14 2008

Status

approved