A097434 Value of C in y = x^2 + 5x + C such that y is prime for all x = 0 to 3.

5, 17, 23, 47, 83, 167, 227, 257, 443, 563, 593, 677, 1277, 1283, 1613, 1973, 2333, 2837, 2903, 3533, 5393, 5843, 6197, 6263, 6977, 7523, 8087, 8363, 11807, 12473, 12893, 13463, 13907, 14537, 14717, 15077, 15263, 15377, 17093, 17327, 19913

Offset: 1

Author

Ray G. Opao, Aug 22 2004

Keywords

• nonn

Examples

			a(2) = 17: y = x^2+5x+17.
If x = 0; y = 0+0+17 = 17, which is prime.
If x = 1; y = 1+5+17 = 23, which is prime.
If x = 2; y = 4+10+17 = 31, which is prime.
If x = 3; y = 9+15+17 = 41, which is prime.
		

Programs

PARI

isok(n) = {for (x=0, 3, if (! isprime(x^2+5*x+n), return (0));); return (1);} \\ Michel Marcus, Aug 09 2013