A263875 a(n) = least positive k such that A263874(n) + 2^k is prime.

1, 2, 3, 4, 5, 8, 10, 20, 29, 955, 4583176, 9092392

Offset: 1

Author

Arkadiusz Wesolowski, Oct 28 2015

Keywords

• nonn
• hard
• more

Comments

A263874 gives where the records occur.

Links

• mersenneforum.org, Five or Bust - The Dual Sierpinski Problem

Crossrefs

Cf. A067760, A263874.

Programs

PARI

a=1; forstep(n=1, 773, 2, k=1; while(!ispseudoprime(n+2^k), k++); if(k+1>a, print1(k, ", "); a=k+1));