A089311 Write n in binary; a(n) = number of 0's in rightmost block of zeros, after dropping any trailing 0's.

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

Offset

0,10

Links

Harvey P. Dale, Table of n, a(n) for n = 0..1000

Example

9 = 1001 so a(9) = 2.

Mathematica

bd[n_]:=Module[{s=Split[IntegerDigits[n, 2]]}, Which[Length[s]<3, 0, MemberQ[ Last[s], 1], Length[s[[-2]]], True, Length[s[[-3]]]]]; Array[bd, 120, 0] (* Harvey P. Dale, Dec 29 2013 *)

Prog

(PARI) a(n)=local(b, c, s):b=binary(n):c=length(b):while(!b[c], c=c-1):while(c>0&&b[c], c=c-1): if(c<=0, 0, s=0:while(!b[c], c=c-1:s=s+1):s) \\ Ralf Stephan

Crossrefs

Cf. A089309-A089313. Different from A086784.

Sequence in context: A293133 A178471 A160381 * A086784 A104162 A145679

Adjacent sequences: A089308 A089309 A089310 * A089312 A089313 A089314

Keyword

nonn,base

Author

N. J. A. Sloane, Dec 22 2003

Extensions

More terms from Ralf Stephan, Feb 01 2004

Status

approved