A128874 - OEIS

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A128874

Numbers n such that 16 greater than the product of the first n lesser twin primes is prime.

1, 2, 3, 469 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	COMMENTS	`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.`
	FORMULA	`Define twinl#(n)as the product of the first n lesser twin primes. Then if twinl#(n)+ 16 is prime, list n.`
	EXAMPLE	`Twinl#(3) + 16 = 3511+16 = 181 the third prime 16 greater than twinl#(3).`
	PROG	`(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)) }`
	CROSSREFS	`Sequence in context: A066849 A071219 A109855 * A196070 A173342 A090510` `Adjacent sequences: A128871 A128872 A128873 * A128875 A128876 A128877`
	KEYWORD	`more,nonn`
	AUTHOR	`Cino Hilliard (hillcino368(AT)hotmail.com), May 08 2007`

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Last modified February 17 13:18 EST 2012. Contains 206031 sequences.