A221903 Primes of the form 2*n^2 + 42*n + 19.

163, 811, 1423, 1783, 2179, 3079, 3583, 9739, 11503, 13411, 14419, 17659, 22483, 25111, 26479, 27883, 42139, 49411, 55243, 57259, 70111, 72379, 77023, 79399, 86743, 97039, 116443, 119359, 125299, 140779, 181603, 188911, 207811

Offset: 1

Author

Vincenzo Librandi, Feb 01 2013

Keywords

• nonn
• easy

Comments

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

2*a(n) + 403 is a square. - Vincenzo Librandi, Apr 10 2015

Links

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

Crossrefs

Cf. Primes of the form 2*n^2+2*(2*k+3)*n+(2*k+1): A176549 (k=0), A154577 (k=2), A154592 (k=3), A154601 (k=4), A217494 (k=7), this sequence (k=9), A217495 (k=10), A217496 (k=11), A217497 (k=12), A217498 (k=13), A217499 (k=16), A217500 (k=17), A217501 (k=18), A217620 (k=19), A217621 (k=21).

Cf. A054723.

Programs

Magma

[a: n in [1..500] | IsPrime(a) where a is 2*n^2 + 42*n + 19];

Mathematica

Select[Table[2 n^2 + 42 n + 19, {n, 500}], PrimeQ]