A031142 Position of rightmost 0 (including leading 0) in 2^n increases.

0, 4, 7, 13, 14, 18, 24, 27, 31, 34, 37, 49, 51, 67, 72, 76, 77, 81, 86, 129, 176, 229, 700, 1757, 1958, 7931, 57356, 269518, 411658, 675531, 749254, 4400728, 18894561, 33250486, 58903708, 297751737, 325226398, 781717865, 18504580518, 27893737353

Offset: 1

Author

Matthew Cook, Dan Hoey, Eric W. Weisstein, David W. Wilson

Keywords

• nonn
• base

Comments

"Positions" are counted 0,1,2,3,... starting with the least significant digit.

86 is the last n for which the rightmost zero is the leading zero.

Links

• Alan Griffiths, Table of n, a(n) for n = 1..46 (reuploaded from a-file by _Georg Fischer_, Jan 21 2019)

Crossrefs

Cf. A031140, A031141, A031142, A031143.

Programs

Mathematica

best = 0;
Select[Range[0, 10000],
 If[(t = First@
       First@StringPosition[StringReverse@("0" <> ToString@(2^#)),
"0"]) > best, best = t; True] &] (* Robert Price, Oct 11 2019 *)

Extensions

a(39)-a(41) added (to match A031140) by Tanya Khovanova, Feb 02 2011

a(42)-a(44) from Alan Griffiths, Jan 25 2012