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

4,2

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).

Links

Table of n, a(n) for n=4..40.

Crossrefs

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

Sequence in context: A323375 A140366 A167817 * A181520 A256736 A123073

Adjacent sequences: A153398 A153399 A153400 * A153402 A153403 A153404

Keyword

nonn,more

Author

Vladimir Shevelev, Dec 25 2008

Status

approved