The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A217495 Primes of the form 2*n^2 + 46*n + 21. 9
 769, 1381, 1741, 2137, 3037, 3541, 4657, 7321, 9697, 22441, 26437, 30757, 35401, 37021, 38677, 47497, 49369, 55201, 61357, 72337, 79357, 81769, 96997, 99661, 105097, 134437, 188869, 207769, 211657, 227569, 256801, 306301, 330241, 469237, 480937, 492781, 510817 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Conjecture: 2^a(n)-1 is not prime; in other words, these primes are included in A054723. 2*a(n)+487 is a square. - Vincenzo Librandi, Mar 04 2013 LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..3000 MATHEMATICA Select[Table[2 n^2 + 46 n + 21, {n, 500}], PrimeQ] PROG (Magma) [a: n in [1..500] | IsPrime(a) where a is 2*n^2+46*n+21]; 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=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. Subsequence of A002144. Sequence in context: A308789 A046505 A229854 * A216646 A252077 A236784 Adjacent sequences: A217492 A217493 A217494 * A217496 A217497 A217498 KEYWORD nonn,easy AUTHOR Vincenzo Librandi, Oct 09 2012 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified April 1 10:36 EDT 2023. Contains 361689 sequences. (Running on oeis4.)