A136610 Number of odd digits in Fibonacci numbers.

0, 1, 1, 0, 1, 1, 0, 2, 1, 1, 2, 1, 1, 2, 3, 1, 2, 4, 1, 2, 2, 2, 5, 2, 1, 3, 5, 3, 5, 3, 1, 3, 4, 4, 3, 3, 5, 5, 4, 3, 6, 5, 4, 5, 5, 7, 7, 7, 4, 5, 4, 5, 6, 9, 5, 6, 8, 6, 7, 4, 6, 7, 8, 7, 7, 9, 7, 7, 5, 7, 10, 8, 6, 10, 8, 9, 6, 10, 8, 6, 6

Offset: 0

Author

Parthasarathy Nambi, May 11 2008

Keywords

• nonn
• base

Examples

			1597 = Fibonacci(17) and has four odd digits, so a(17) = 4.
		

Links

• Ron Knott, The Fibonacci numbers.

Crossrefs

Cf. A000045, A138468, A196564.

Cf. A060384, A085855. - R. J. Mathar, Jul 08 2009

Programs

Maple

nodss := proc(n) local dgs,d; dgs := convert(n,base,10) ; add( d mod 2, d=dgs) ; end: A136610 :=proc(n) nodss(combinat[fibonacci](n)) ; end: seq( A136610(n),n=0..80) ; # R. J. Mathar, Jul 08 2009

Mathematica

a[n_]:=Total[Boole[OddQ/@IntegerDigits[Fibonacci[n]]]] (* James C. McMahon, May 06 2025 *)

Formula

a(n) = A196564(A000045(n)). - Michel Marcus, May 06 2025

a(n) = A060384(n) - A138468(n). - James C. McMahon, Jun 07 2025

Extensions

a(13) corrected and more terms added by R. J. Mathar, Jul 08 2009