A230663 Least prime p such that x^2 + 3*x + p produces primes for x = 0..n-1 but not x = n.

2, 67, 3, 349, 79, 439, 21559, 14713, 13, 8123233, 223, 3468214093

Offset

1,1

Comments

a(39) = 43 and all other terms > 128865958933.

Links

Table of n, a(n) for n=1..12.

R. A. Mollin, Prime-producing quadratics, Amer. Math. Monthly 104 (1997), 529-544.

Mathematica

Table[p = 2; While[! (Union[Table[PrimeQ[x^2 + 3*x + p], {x, 0, n - 1}]] == {True} && PrimeQ[n^2 + 3*n + p] == False), p = NextPrime[p]]; p, {n, 9}] (* T. D. Noe, Oct 29 2013 *)

Crossrefs

Cf. A164926.

Sequence in context: A335546 A139822 A119552 * A016535 A245097 A139864

Adjacent sequences: A230660 A230661 A230662 * A230664 A230665 A230666

Keyword

nonn,more

Author

Zak Seidov, Oct 27 2013

Status

approved