A108316 Least k such that (k*n)^2 + k*n -1 and (k*n)^2 + k*n +1 are twin primes.

2, 1, 1, 2, 1, 1, 3, 1, 6, 2, 6, 2, 2, 27, 1, 11, 9, 3, 2, 1, 1, 3, 6, 1, 2, 1, 2, 20, 7, 24, 5, 9, 2, 107, 13, 8, 8, 1, 9, 14, 1, 9, 5, 4, 9, 3, 3, 6, 14, 1, 3, 12, 10, 1, 9, 10, 8, 5, 1, 12

Offset

1,1

Links

Table of n, a(n) for n=1..60.

Example

(2*1)^2 + 2*1 -1 = 5, (2*1)^2 + 2*1 +1 = 7, 5 and 7 twin primes so k(1)=2

Crossrefs

Sequence in context: A284315 A262928 A228429 * A322426 A335438 A145574

Adjacent sequences: A108313 A108314 A108315 * A108317 A108318 A108319

Keyword

nonn

Author

Pierre CAMI, Jul 25 2005

Status

approved