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A165557 Primes of the form (p^2-1)/4-p where p are also primes. 2
5, 19, 29, 71, 109, 181, 379, 419, 811, 1259, 1481, 2549, 2861, 3079, 4159, 4691, 7309, 8009, 8929, 13339, 17029, 18089, 19739, 21169, 23869, 24179, 27059, 35531, 37441, 39799, 41411, 43889, 46439, 47741, 48619, 53129, 59779, 61751, 67339, 89101, 93329 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The associated primes p are in A165349.

LINKS

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

EXAMPLE

a(1) = 5 = (7^2-1)/4-7 generated by A165349(1)=7.

a(2) = 19 = (11^2-1)/4-11 generated by A165349(2)=11.

MATHEMATICA

Select[Table[(p^2 - 1)/4 - p, {p, Prime[Range[200]]}], PrimeQ] (* Vincenzo Librandi, Oct 12 2012 *)

PROG

(MAGMA) [a: p in PrimesInInterval(5, 700) | IsPrime(a) where a is (p^2 - 1) div 4 - p ]; // Vincenzo Librandi, Oct 12 2012

CROSSREFS

Cf. A165349.

Sequence in context: A115103 A241043 A045457 * A138242 A163076 A122729

Adjacent sequences:  A165554 A165555 A165556 * A165558 A165559 A165560

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi, Sep 22 2009

EXTENSIONS

Entries checked by R. J. Mathar, Sep 26 2009

STATUS

approved

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Last modified November 20 17:42 EST 2014. Contains 249753 sequences.