

A128824


First prime which is 2k greater than the product of lesser twin primes.


0



5, 7, 11, 13, 17, 19, 23, 37, 29, 31, 47, 37, 41, 43, 47, 61, 53, 67, 59, 61, 227, 67, 71, 73, 89, 79, 83, 97, 89, 103, 107, 97, 101, 103
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OFFSET

1,1


COMMENTS

In the example, 37 is the only number possible for 2k=22. Twinl#(1)= 3 and 3+22 = 25, not prime. Twinl#(n), n>2, is a multiple of 11 so adding 22 will always result in a multiple of 11 and not prime. If k is a multiple of a lesser twin prime, then the number of primes in twinl#(n)+2k is finite.


LINKS

Table of n, a(n) for n=1..34.


FORMULA

Define twinl#(n)as the product of the first n lesser twin primes. Then if twinl#+2k k=1,2,3... is prime, list it.


EXAMPLE

Twinl#(2) + 2*11 = 37, the first prime 22 greater than twinl#(2).


PROG

(PARI) twiprimesl(n, a) = { local(pr, x, y, j); for(j=1, n, pr=1; for(x=1, j, pr*=twinl(x); ); y=pr+a; if(ispseudoprime(y), print1(y", ") ) ) } twinl(n) = \The nth lower twin prime { local(c, x); c=0; x=1; while(c<n, if(isprime(prime(x)+2), c++); x++; ); return(prime(x1)) }


CROSSREFS

Sequence in context: A118941 A096547 A216524 * A098420 A309726 A093495
Adjacent sequences: A128821 A128822 A128823 * A128825 A128826 A128827


KEYWORD

nonn


AUTHOR

Cino Hilliard, May 08 2007


STATUS

approved



