1,2

It is interesting from the example that the first three primes 19,31 and 181 greater than twinl#(n) + 16 are all greater twin primes. The next PRP is the 1824 digit number twinl#(469) + 16 and is not part of a twin prime pair.

Define twinl#(n)as the product of the first n lesser twin primes. Then if twinl#(n)+ 16 is prime, list n.

Twinl#(3) + 16 = 3*5*11+16 = 181 the third prime 16 greater than twinl#(3).

(PARI) twiprimesl2(n, a) = { local(pr, x, y, j); for(a=0, n, for(j=1, n, pr=1; for(x=1, j, pr*=twinl(x); ); y=pr+2^a; if(ispseudoprime(y), print1(y", "); break ) ) ) } twinl(n) = \The n-th lower twin prime { local(c, x); c=0; x=1; while(c<n, if(isprime(prime(x)+2), c++); x++; ); return(prime(x-1)) }

Sequence in context: A066849 A071219 A109855 this_sequence A090510 A004887 A165770

Adjacent sequences: A128871 A128872 A128873 this_sequence A128875 A128876 A128877

more,nonn

Cino Hilliard (hillcino368(AT)hotmail.com), May 08 2007