A113193 Number of times that Lucas(n)-Lucas(i) is prime for i=0..n-3.

1, 1, 0, 1, 0, 1, 1, 0, 2, 2, 1, 1, 1, 2, 0, 1, 0, 1, 3, 1, 0, 2, 2, 1, 3, 1, 0, 1, 0, 3, 3, 0, 1, 2, 1, 1, 2, 1, 0, 2, 1, 0, 4, 2, 1, 3, 0, 1, 2, 1, 0, 1, 0, 2, 0, 1, 2, 1, 3, 0, 2, 1, 2, 1, 0, 0, 2, 3, 0, 1, 1, 3, 0, 1, 0, 1, 0, 0, 4, 1, 1, 1, 2, 1, 0, 1, 0, 3, 1, 1, 0, 2, 4, 1, 1, 0, 3, 0, 0, 5, 0, 1, 2, 1, 0

Offset: 3

Author

T. D. Noe, Oct 17 2005

Keywords

• nonn

Comments

We exclude i=n-2 and i=n-1 because they yield Lucas(n-2) and Lucas(n-1), respectively. Sequence A113194 lists the n for which a(n)=0.

Crossrefs

Cf. A113192 (primes that are the difference of two Lucas numbers).

Programs

Mathematica

Lucas[n_] := Fibonacci[n+1]+Fibonacci[n-1]; Table[cnt=0; Do[If[PrimeQ[Lucas[n]-Lucas[i]], cnt++ ], {i, 0, n-3}]; cnt, {n, 3, 150}]