A244571 Smallest prime p >= prime(n) such that p*prime(n)-2 is prime.

3, 5, 7, 23, 13, 23, 19, 41, 29, 61, 37, 59, 43, 47, 71, 107, 61, 73, 71, 97, 109, 113, 89, 157, 113, 103, 107, 127, 167, 127, 131, 149, 139, 179, 163, 163, 181, 227, 173, 251, 199, 191, 223, 257, 229, 211, 223, 233, 271, 233, 239, 271, 281, 257, 443, 389, 373

Offset

2,1

Comments

See comment in A244572.

Links

Jens Kruse Andersen, Table of n, a(n) for n = 2..10000

V. Shevelev, Theorems on twin primes-dual case, arXiv:0912.4006 [math.GM], 2009-2014. Sections 10, 14.

Mathematica

a[n_] := For[p = Prime[n], True, p = NextPrime[p], If[PrimeQ[p Prime[n] - 2], Return[p]]];
Table[a[n], {n, 2, 60}] (* Jean-François Alcover, Nov 18 2018 *)

Prog

(PARI) s=[]; for(n=2, 100, p=q=prime(n); while(!isprime(p*q-2), p=nextprime(p+1)); s=concat(s, p)); s \\ Colin Barker, Jun 30 2014

Crossrefs

Cf. A244570, A242719, A242720.

Sequence in context: A370204 A239282 A171015 * A269721 A084424 A137978

Adjacent sequences: A244568 A244569 A244570 * A244572 A244573 A244574

Keyword

nonn

Author

Vladimir Shevelev, Jun 30 2014

Extensions

More terms from Peter J. C. Moses, Jun 30 2014

Status

approved