A031141 Position of rightmost digit 0 in 2^A031140(n).

2, 5, 8, 11, 12, 13, 14, 23, 36, 38, 54, 57, 59, 93, 115, 119, 120, 121, 136, 138, 164, 174, 176, 191, 196, 212, 217, 227, 233, 249

Offset: 1

Author

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

Keywords

• nonn
• base
• more

Comments

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

Links

• Eric Weisstein's World of Mathematics, Zero.

Crossrefs

Cf. A031140, A031142, A031143.

Programs

Mathematica

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

PARI

m=0;for(k=0,oo,d=digits(2^k);for(j=0,#d-1,d[#d-j]||(j>m&&print1(m=j,",")||break))) \\ M. F. Hasler, Jun 21 2018

Extensions

More terms from Dan Hoey