login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A217497 Primes of the form 2*n^2 + 54*n + 25. 10
421, 673, 2473, 4561, 5821, 9601, 12301, 14281, 19861, 30661, 32173, 33721, 61261, 67741, 84121, 94273, 107773, 110581, 122173, 134341, 170773, 203821, 207673, 223441, 227473, 265381, 274201, 287701, 344941, 365173, 391273, 396601, 418273, 423781, 469141 (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) + 679 is a square. - Vincenzo Librandi, Apr 10 2015

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..3000

MATHEMATICA

Select[Table[2 n^2 + 54 n + 25, {n, 500}], PrimeQ]

PROG

(MAGMA) [a: n in [1..500] | IsPrime(a) where a is 2*n^2+54*n+25];

CROSSREFS

Cf. A054723, A176549, A217494.

Subsequence of A002144.

Sequence in context: A031784 A268859 A051648 * A333640 A146358 A050962

Adjacent sequences:  A217494 A217495 A217496 * A217498 A217499 A217500

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 | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 2 18:17 EDT 2020. Contains 334787 sequences. (Running on oeis4.)