A104994 Least k(n)>1 such that n*k(n)^2+n*k(n)+1 is a prime > (n-1)*k(n-1)^2+(n-1)*k(n-1)+1 or 0 if n=4 as no prime possible.

2, 2, 2, 0, 2, 2, 2, 3, 3, 6, 6, 7, 8, 8, 12, 14, 14, 19, 21, 21, 22, 27, 27, 28, 29, 29, 30, 30, 34, 37, 38, 39, 39, 41, 41, 43, 50, 52, 54, 54, 56

Offset

1,1

Comments

sequence of the primes given in A104995

Links

Table of n, a(n) for n=1..41.

Example

1*2^2+1*2+1=7 prime so k(1)=2
2*2^2+2*2+1=13 prime > 7 so k(2)=2
3*2^2+3*2+1=19 prime > 13 so k(3)=2
5*2^2+5*2+1=31 prime > 19 so k(5)=2

Crossrefs

Cf. A104995.

Sequence in context: A307521 A328995 A036476 * A118664 A223175 A322213

Adjacent sequences: A104991 A104992 A104993 * A104995 A104996 A104997

Keyword

nonn

Author

Pierre CAMI, Mar 31 2005

Status

approved