A144411 Odd nonprime gaps adjusted to be {2,1,0,-1}: a(n)=A067970(n)/2-2.

2, 1, 1, 0, -1, 1, -1, 0, 1, 0, -1, 0, -1, 1, -1, 0, 1, -1, 0, 0, -1, 0, -1, -1, 0, 1, 1, 0, -1, -1, -1, -1, -1, 0, 0, -1, 1, -1, -1, -1, 1, -1, 0, -1, 0, 0, -1, 0, -1, 1, -1, -1, -1, 1, 1, -1, -1, -1, -1, 0, -1, -1, -1, -1, 0, 1, 0, -1, 1, -1, -1, -1, 0, -1, 0, -1, 0, -1, 1, -1, 0, 1, -1, -1, -1, 0, -1, -1, -1, -1, -1, 0, 1, 0, -1, -1, -1, -1, -1, 0

Offset: 1

Author

Roger L. Bagula and Gary W. Adamson, Sep 30 2008

Keywords

• uned
• sign

Programs

Mathematica

b = Flatten[Table[If[PrimeQ[2*n + 1], {}, 2*n + 1], {n, 0, 200}]]; c = Table[(b[[n + 1]] - b[[n]])/2 - 2, {n, 1, Length[b] - 1}]

Formula

a(n)=A067970(n)/2-2.