A135023 (NextPrime[6*n] - PreviousPrime[6*n])/2.

1, 1, 1, 3, 1, 3, 1, 3, 3, 1, 3, 1, 3, 3, 4, 4, 1, 1, 7, 7, 7, 3, 1, 5, 1, 3, 3, 3, 3, 1, 5, 1, 1, 6, 6, 6, 6, 1, 3, 1, 5, 3, 3, 3, 1, 3, 1, 5, 7, 7, 7, 1, 7, 7, 7, 3, 5, 1, 3, 4, 4, 3, 3, 3, 4, 4, 4, 4, 5, 1, 5, 1, 3, 3, 4, 4, 1, 6, 6, 4, 4, 4, 4, 3, 6, 6, 1, 9, 9, 9, 3, 5, 3, 3, 1, 3, 5, 3, 3, 1, 3, 3, 1, 6, 6

Offset: 1

Author

Zak Seidov, Feb 10 2008

Keywords

• nonn

Comments

a(n)=1 if 6n -/+ 1 are twin primes.

Links

• G. C. Greubel, Table of n, a(n) for n = 1..1000

Programs

Mathematica

Table[(NextPrime[6*n] - NextPrime[6*n, -1])/2, {n, 1, 25}] (* G. C. Greubel, Sep 17 2016 *)