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

1,1

Comments

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

Links

Table of n, a(n) for n=1..30.

Eric Weisstein's World of Mathematics, Zero.

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 *)

Prog

(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

Crossrefs

Cf. A031140, A031142, A031143.

Sequence in context: A056734 A019995 A188802 * A143263 A327138 A102624

Adjacent sequences: A031138 A031139 A031140 * A031142 A031143 A031144

Keyword

nonn,base,more

Author

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

Extensions

More terms from Dan Hoey

Status

approved