A202090 a(n) = Fibonacci(n) - p, where p is the largest prime < Fibonacci(n).

2, 1, 2, 2, 3, 2, 6, 5, 4, 4, 3, 4, 14, 5, 4, 2, 7, 4, 8, 17, 8, 14, 31, 14, 10, 37, 20, 26, 9, 20, 22, 11, 6, 12, 15, 32, 18, 17, 18, 16, 43, 24, 6, 17, 20, 26, 27, 20, 6, 9, 12, 34, 29, 36, 30, 47, 48, 4, 45, 32, 54, 27, 132, 22, 31, 4, 32, 11, 12, 60, 7, 76

Offset: 5

Author

Michel Lagneau, Dec 11 2011

Keywords

• nonn

Examples

			a(7) = Fibonacci(7) - 19 = 21-19 = 2;
a(11) = Fibonacci(11) - 83 = 89 - 83 = 6.
		

Crossrefs

Cf. A000045.

Programs

Maple

A049711 := proc(n)
    n-prevprime(n) ;
end proc:
A202090 := proc(n)
    A049711(combinat[fibonacci](n) );
end proc:
seq(A202090(n),n=5..80) ; # R. J. Mathar, Dec 13 2011

Mathematica

f[n_]:=Module[{nf=Fibonacci[n]},nf-NextPrime[nf,-1]];f/@Range[5,90]

Formula

a(n) = A049711(A000045(n)). - R. J. Mathar, Dec 13 2011