

A079140


Numbers n such that (Product of first n twin prime pair averages [A014574])  1 is prime.


0



1, 2, 7, 11, 16, 32, 402, 1107, 1829, 2584, 3124, 6936
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OFFSET

1,2


COMMENTS

Some of the larger entries may only correspond to probable primes.


LINKS

Table of n, a(n) for n=1..12.


EXAMPLE

a(2) = 2 because the product of the first two terms of A014574  1, 4 * 61 = 23, is prime.


MATHEMATICA

seq = {1}; prod = 4; k = 1; Do[If[AllTrue[6 n + {1, 1}, PrimeQ], prod *= 6 n; k++; If[PrimeQ[prod  1], AppendTo[seq, k]]], {n, 1, 5000}]; seq (* Amiram Eldar, Dec 14 2019 *)


PROG

(PARI) {atm(N)=local(t, c); t=1; c=0; forprime(p=2, N, if(isprime(p+2), t*=p+1; c++; if(isprime(t1), print1(c, ", "))))}


CROSSREFS

Cf. A014574.
Sequence in context: A190518 A190750 A049635 * A176897 A166005 A243009
Adjacent sequences: A079137 A079138 A079139 * A079141 A079142 A079143


KEYWORD

nonn,more


AUTHOR

Jason Earls, Dec 26 2002


EXTENSIONS

a(8)a(12) from Amiram Eldar, Dec 14 2019


STATUS

approved



