A090795 - OEIS

A090795

a(n) = lesser of a pair of twin primes p, q=p+2 such that product of first n primes plus p is a prime and also product of first n primes plus q is a prime.

3, 5, 11, 17, 29, 59, 41, 41, 641, 101, 419, 101, 269, 179, 107, 827, 1319, 311, 1949, 1667, 1619, 1787, 2267, 4931, 4241, 1619, 461, 809, 12107, 191, 1301, 1721, 13679, 4217, 3527, 11717, 11351, 17789, 23057, 17489, 65579, 22271, 16451, 6299, 1019

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Table of n, a(n) for n=1..45.

EXAMPLE

a(3)=11 because prime(3)=5, primorial(5)=5*3*2=30, 11 and 13 are twin primes and 30+11 = 41 and 43 are also twin primes.

MATHEMATICA

Do[p = Fold[ Times, 1, Prime[ Range[n]]]; k = 2; While[q = Prime[k]; !PrimeQ[q + 2] || !PrimeQ[p + q] || !PrimeQ[p + q + 2], k++ ]; Print[q], {n, 1, 45}] (* Robert G. Wilson v, Feb 10 2004 *)

CROSSREFS

Cf. primorials A002110, twin primes A001359.

Sequence in context: A147015 A147023 A108402 * A087732 A278053 A174916

Adjacent sequences: A090792 A090793 A090794 * A090796 A090797 A090798

KEYWORD

easy,nonn

AUTHOR

Donald S. McDonald, Feb 10 2004

EXTENSIONS

More terms from Ray Chandler and Robert G. Wilson v, Feb 10 2004

STATUS

approved