A031143 Position of rightmost 0 (including leading 0) in 2^A031142(n).

1, 2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 15, 16, 21, 22, 23, 24, 25, 26, 36, 38, 54, 57, 59, 93, 115, 119, 120, 121, 136, 138, 164, 174, 176, 191, 196, 212, 217, 227, 233, 249, 250, 260, 268, 275, 308

Offset: 1

Author

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

Keywords

• nonn

Comments

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

Crossrefs

Cf. A031140, A031141, A031142, A031143.

Programs

Mathematica

best = 0; lst = {};
x = Select[Range[0, 10000],
  If[(t = First@
        First@StringPosition[StringReverse@("0" <> ToString@(2^#)),
          "0"]) > best, best = t; AppendTo[lst, t - 1]; True] &] ; lst (* Robert Price, Oct 11 2019 *)

Extensions

More terms from Dan Hoey

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

a(45) from Alan Griffiths, Feb 01 2012

a(46) from Alan Griffiths, Mar 09 2012