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A115058 Primes p such that 3p+2 is not prime. 2
2, 11, 31, 41, 47, 53, 61, 67, 71, 73, 101, 107, 109, 113, 131, 137, 151, 157, 179, 181, 191, 193, 211, 223, 229, 241, 251, 263, 271, 277, 281, 283, 307, 311, 331, 347, 359, 373, 379, 389, 401, 421, 431, 443, 449, 461, 463, 467, 487, 491, 509, 521, 541, 547 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Complement of A023208 in the prime numbers A000040.

Primes p that are also the largest prime factor of p(p^2-1)(3p+2)/24.

REFERENCES

Number Theory, George E. Andrews 1971, Dover Publications New York, p 4.

LINKS

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

EXAMPLE

p=11, p(p^2-1)(3p+2)/24 = 1925 = 5*5*7*11.

MATHEMATICA

a={}; Do[p=Prime[n]; If[ !PrimeQ[3*p+2], AppendTo[a, p]], {n, 8^2}]; a - Vladimir Joseph Stephan Orlovsky, Apr 29 2008

Select[Prime[Range[100]], ! PrimeQ[3 # + 2]&] (* Vincenzo Librandi, Apr 17 2013 *)

PROG

(MAGMA) [p: p in PrimesUpTo(600) | not IsPrime(3*p + 2)]; // Vincenzo Librandi, Apr 17 2013

CROSSREFS

Sequence in context: A094005 A190154 A187830 * A158295 A213898 A085041

Adjacent sequences:  A115055 A115056 A115057 * A115059 A115060 A115061

KEYWORD

easy,nonn

AUTHOR

Cino Hilliard, Feb 28 2006

EXTENSIONS

Edited by Max Alekseyev, Feb 06 2010

STATUS

approved

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Last modified November 14 04:56 EST 2019. Contains 329110 sequences. (Running on oeis4.)