A097444 Second occurrence where n# + p is prime for primes p = 3,5,...

7, 13, 41, 227, 2339, 30059, 510551, 9699727, 223092917, 6469693319, 200560490213, 7420738134911, 304250263527317, 13082761331670097, 614889782588491519, 32589158477190044803, 1922760350154212639159

Offset

2,1

Comments

Care has to be taken to start with a large enough n to be sure terms are not missed. Here we used n=100.

Links

Table of n, a(n) for n=2..18.

Formula

n# is n primorial = product of primes 2*3*5*...*p<=n

Example

5# = 2*3*5 = 30. 30+7 = 37 first prime,30+11 = 41 second prime.

Prog

(PARI) primorp2(n) = { pr=1; for(x=1, n, f=1; pr*=prime(x); for(m=1, n, y=pr+prime(m); if(isprime(y), f=1; for(m=m+1, n, y=pr+prime(m); if(isprime(y), print1(y", "); f=0; break, f=1)); ); if(f==0, break) ) ) }

Crossrefs

Sequence in context: A045464 A134854 A330671 * A241718 A259184 A259186

Adjacent sequences: A097441 A097442 A097443 * A097445 A097446 A097447

Keyword

nonn

Author

Cino Hilliard, Aug 23 2004

Status

approved