A253592 -id:A253592 - cp's OEIS frontend

A191456 Primes p such that the polynomial x^2+x+p generates only primes for x=1..9.

11, 17, 41, 844427, 51448361, 86966771, 122983031, 180078317, 960959381, 1278189947, 1761702947, 1829187287, 2426256797, 2911675511, 3013107257, 4778888351, 5221343711

Offset: 1

Zak Seidov, Jun 02 2011

nonn

Charles R Greathouse IV, Table of n, a(n) for n = 1..2713

Generates primes for x=1..k: A001359 (1), A022004 (2), A172454 (3), A187057 (4), A187058 (5), A144051 (6), A187060 (7), A190800 (8), this sequence (9), A191457 (10), A191458 (11), A253592 (12), A253605 (13). Each is by definition a subsequence of preceding sequences.
Subsequence such that x=10 gives a composite number: A211238.
Cf. A160548, A164926.

is(n)=for(x=0,9, if(!isprime(x^2+x+n), return(0))); 1 \\ Charles R Greathouse IV, Sep 14 2015

A253605 Primes p such that the polynomial x^2 + x + p generates only primes for x=1..13.

Original entry on oeis.org

17, 41, 27649987598537, 30431463129071, 58326356511581, 161966446726157, 291598227841757

Offset: 1

Zak Seidov, Jan 05 2015

Subsequence of A253592 and A191458. Cf. A164926.

isok(p) = {for (n=1, 13, if (! isprime(subst(x^2+x+p, x, n)), return (0));); 1;} \\ Michel Marcus, Jan 13 2015

use ntheory qw(:all); local $| = 1; my $lo = 2; my $hi = 2*$lo; while (1) { print "$, " for sieve_prime_cluster($lo, $hi, map { $*($+1) } 1..13); $lo = $hi+1; $hi = 2*$lo } # _Daniel Suteu, Dec 22 2024

a(5)-a(7) from Daniel Suteu, Dec 22 2024

cp's OEIS Frontend

A191456 Primes p such that the polynomial x^2+x+p generates only primes for x=1..9.

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