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A256374 Primes of the form 7*k^2 + 7*k + 17. 1
17, 31, 59, 101, 157, 227, 311, 409, 521, 647, 787, 941, 1109, 1291, 1487, 1697, 2411, 2677, 2957, 3251, 3559, 3881, 4217, 4567, 4931, 5309, 5701, 6961, 8837, 9341, 9859, 10391, 10937, 11497, 12071, 12659, 13877, 15809, 16481, 17167, 19309, 20051, 20807, 21577, 23159, 23971 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The values k=0 through 15 all give primes.

LINKS

Felix Fröhlich, Table of n, a(n) for n = 1..10000

EXAMPLE

For k=15 we get 1697, a prime.

For k=16 we get 1921 = 17*113, not a prime, so not a term of the sequence.

MATHEMATICA

Select[Table[7 n^2 + 7 n +17, {n, 0, 600}], PrimeQ]

PROG

(MAGMA) [ a: n in [0..200] | IsPrime(a) where a is 7*n^2 + 7*n + 17 ];

(PARI) for(k=0, 1e2, if(ispseudoprime(7*k^2+7*k+17), print1(7*k^2+7*k+17, ", "))) \\ Felix Fröhlich, Apr 01 2015

CROSSREFS

Cf. A256375.

Sequence in context: A260805 A267781 A270441 * A286512 A087166 A167496

Adjacent sequences:  A256371 A256372 A256373 * A256375 A256376 A256377

KEYWORD

nonn,easy

AUTHOR

Avi Friedlich, Mar 26 2015

EXTENSIONS

Corrected by Vincenzo Librandi, Mar 27 2015

Edited by N. J. A. Sloane, Mar 27 2015

STATUS

approved

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Last modified September 20 01:54 EDT 2020. Contains 337260 sequences. (Running on oeis4.)