A137919 (Nextprime(24n)-previousprime(24n))/2.

3, 3, 1, 4, 7, 5, 3, 1, 6, 1, 3, 5, 1, 3, 4, 3, 4, 1, 4, 4, 3, 9, 5, 3, 1, 6, 3, 6, 5, 4, 4, 4, 5, 5, 7, 7, 10, 4, 4, 7, 4, 6, 1, 5, 9, 3, 3, 1, 5, 4, 3, 6, 9, 3, 1, 17, 3, 9, 7, 4, 6, 1, 6, 6, 4, 7, 1, 5, 10, 12, 5, 5, 3, 9, 6, 4, 7, 1, 6, 9, 8, 11, 3, 3, 7, 3, 1, 1, 3, 4, 12, 3, 8, 8, 4, 6, 11, 3, 3, 6, 7, 6

Offset: 1

Author

Zak Seidov, Feb 23 2008

Keywords

• nonn

Comments

a(n)=1 if 24n -/+ 1 are twin primes.

Corresponding n's are in A137920.

Crossrefs

Cf. A124519, A135023, A135368, A137876, A137877, A137920.

Programs

Mathematica

Table[(NextPrime[24n]-NextPrime[24n,-1])/2,{n,110}] (* Harvey P. Dale, Apr 15 2015 *)

PARI

a(n) = (nextprime(24*n) - precprime(24*n))/2; \\ Michel Marcus, Oct 13 2013