A248526 Least prime p such that q = (3+p)/2^n is prime.

2, 3, 5, 13, 29, 61, 317, 3709, 509, 1021, 11261, 4093, 20477, 16381, 180221, 229373, 1900541, 655357, 15990781, 1048573, 5242877, 4194301, 180355069, 16777213, 117440509, 436207613, 738197501, 671088637, 53687090, 2684354557, 5368709117

Offset

0,1

Comments

Corresponding values of q: 5, 2, 2, 2, 2, 2, 5, 29, 2, 2, 11, 2, 5, 2, 11, 7, 29, 5, 61, 2, 5, 2, 43, 2, 7, 13, 11, 5, 2, 5, 5.

Links

Table of n, a(n) for n=0..30.

Mathematica

Do[q = 2; While[! PrimeQ[p = q*2^n - 3], q = NextPrime[q]];
Print[{n, p, q}], {n, 0, 30}]

Crossrefs

Sequence in context: A177502 A072536 A087592 * A324375 A038879 A162390

Adjacent sequences: A248523 A248524 A248525 * A248527 A248528 A248529

Keyword

nonn

Author

Zak Seidov, Oct 07 2014

Status

approved