A153401 a(n) is the least positive number such that in the representation of 2n+1, n>=4, as a sum of the form (2*A000695(k)+a(n))+2(2*A000695(l)+a(n)), both of numbers 2*A000695(k)+a(n) and 2*A000695(l)+a(n) are primes.

1, 3, 3, 3, 1, 3, 3, 3, 1, 3, 3, 3, 1, 3, 3, 3, 7, 3, 9, 1, 1, 5, 3, 7, 9, 3, 7, 1, 1, 19, 3, 0, 5, 7, 3, 3, 5

Offset: 4

Author

Vladimir Shevelev, Dec 25 2008

Keywords

• nonn
• more

Comments

For a given c>=3, every odd N>=3c is a unique sum of the form (2*A000695(k)+c) +2(2*A000695(l)+c).

Crossrefs

Cf. A046927, A103151, A000695, A145812, A147568.