A182238 n^2 + {1,3,7} are primes.

2, 4, 10, 74, 146, 256, 440, 470, 584, 920, 1070, 1156, 1324, 1394, 1420, 2080, 2470, 2600, 3326, 3746, 4796, 5996, 6460, 7160, 7466, 8894, 9164, 9554, 9596, 10490, 10970, 11204, 11246, 11336, 11374, 12314, 12386, 13394, 14290, 15586, 16250, 16330, 17060

Offset: 1

Author

Zak Seidov, Apr 20 2012

Keywords

• nonn

Comments

Under Schinzel's hypothesis H, this sequence is infinite. - Charles R Greathouse IV, Apr 23 2012

Examples

			2^2+{1,3,7}= {5,7,11} all prime, 4^2+{1,3,7}= {17,19,23} all prime.
		

Links

• Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Crossrefs

Intersection of A005574, A049422, A114270.

Programs

PARI

{ forstep ( n=2, 10^6, 2,
    ns = n * n;
    if ( ! isprime( ns+1 ), next() );
    if ( ! isprime( ns+3 ), next() );
    if ( ! isprime( ns+7 ), next() );
    print1(n, ", ");
); }
/* Joerg Arndt, Apr 22 2012 */