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A165352 Primes of the form p + (p^2 - 1)/8, where p is also prime. 4
13, 53, 89, 151, 251, 701, 739, 859, 1429, 1709, 2143, 3001, 4751, 7019, 8513, 10151, 12401, 14533, 17203, 18719, 21319, 23869, 27259, 30133, 41039, 42193, 44549, 45751, 46663, 52973, 82619, 99233, 104651, 114479, 120293, 135979, 138599, 148783, 151523 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Primes of the form k+(k^2-1)/8, where k >0 are prime or composite, are the superset 13, 19, 43, 53, 89, 103 etc.

LINKS

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

FORMULA

a(n) = A165353(n)+(A165353(n)^2-1)/8.

MATHEMATICA

Select[Table[p + (p^2 - 1)/8, {p, Prime[Range[200]]}], PrimeQ] (* Vincenzo Librandi, Oct 12 2012 *)

PROG

(Magma) [a: p in PrimesInInterval(3, 1200) | IsPrime(a) where a is p + (p^2 - 1) div 8 ]; // Vincenzo Librandi, Oct 12 2012

(PARI) forprime(p=3, 1e4, if(isprime(t=p^2>>3+p), print1(t", "))) \\ Charles R Greathouse IV, May 15 2013

CROSSREFS

Cf. A165353, A165354.

Sequence in context: A056255 A141885 A262447 * A262287 A307749 A031905

Adjacent sequences: A165349 A165350 A165351 * A165353 A165354 A165355

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi, Sep 16 2009

EXTENSIONS

More terms from R. J. Mathar, Sep 21 2009

STATUS

approved

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Last modified December 2 05:20 EST 2022. Contains 358485 sequences. (Running on oeis4.)