A140386 Erroneous version of A000040.

5, 23, 29, 43, 107, 109, 137, 163, 197, 199, 227, 229, 317, 347, 359

Offset

1,1

Comments

Original definition: Primes of the form ((x+y)/3+2)/(x-y), where x=prime and y=composite. The current sequence is largely incorrect because many values are missing; for example x=17 with y=16 contributes 13, x=23 with y=22 contributes 17, x=53 with y=52 contributes 37 etc. - R. J. Mathar, Apr 25 2010

All primes up to 100,000 are members. 835 is not a member. - Charles R Greathouse IV, Nov 25 2014

Links

Table of n, a(n) for n=1..15.

Prog

(PARI) is(n)=forprime(x=5, , my(y=(3*n*x-x-6)/(3*n+1)); if(denominator(y)==1 && !isprime(y), return(isprime(n)))) \\ may loop forever if not a member; Charles R Greathouse IV, Nov 25 2014

Crossrefs

Sequence in context: A336300 A243458 A067367 * A105880 A163587 A038922

Adjacent sequences: A140383 A140384 A140385 * A140387 A140388 A140389

Keyword

dead

Author

Juri-Stepan Gerasimov, Aug 28 2008

Status

approved