A243888 Primes of the form 2*n^2+26*n+11.

71, 107, 191, 239, 347, 1031, 1439, 1667, 1787, 2039, 2447, 2591, 3371, 3539, 5231, 5651, 5867, 6311, 7247, 9311, 9587, 10151, 11027, 11939, 12251, 14207, 14891, 19727, 20939, 21767, 23039, 27539, 30431, 34511, 36107, 39971, 41687, 46439, 47051, 56039, 56711

Offset: 1

Author

Vincenzo Librandi, Jun 16 2014

Keywords

• nonn
• easy

Comments

Subsequence of A068231.

Conjecture: except 107, 2^a(n)-1 is not prime; in other words, these primes are included in A054723.

2*a(n) + 147 is a square. - Vincenzo Librandi, Apr 10 2015

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A068231.

Cf. Primes of the form 2*n^2+2*(2*k+3)*n+(2*k+1): A176549 (k=0), A221902 (k=1), A154577 (k=2), A154592 (k=3), A154601 (k=4), this sequence (k=5), A243889 (k=6), A217494 (k=7), A243890 (k=8), A221903 (k=9), A217495 (k=10), A217496 (k=11), A217497 (k=12), A217498 (k=13), A243891 (k=14), A243957 (k=15), A217499 (k=16), A217500 (k=17), A217501 (k=18), A217620 (k=19), A243958 (k=20), A217621 (k=21).

Programs

Magma

[a: n in [1..200] | IsPrime(a) where a is 2*n^2+26*n+11];

Mathematica

Select[Table[2 n^2 + 26 n + 11, {n, 800}], PrimeQ]