|
|
A181611
|
|
Position of rightmost zero in 2^n (including leading zero).
|
|
2
|
|
|
1, 1, 1, 2, 2, 2, 3, 3, 3, 2, 2, 2, 4, 5, 5, 5, 2, 6, 6, 5, 5, 1, 1, 8, 8, 4, 9, 9, 3, 8, 10, 10, 10, 11, 11, 11, 12, 4, 12, 11, 8, 1, 1, 5, 5, 12, 12, 3, 15, 7, 16, 3, 3, 7, 8, 8, 8, 12, 7, 7, 10, 1, 1, 7, 4, 4, 21, 13, 7, 4, 4, 22, 6, 6, 4, 23, 24, 13, 2, 4, 25, 1, 1, 11, 6, 26, 3, 2, 12, 12, 12, 11, 14, 14, 23, 3, 3, 4, 4, 4, 3, 1, 1, 2, 2, 2, 6, 6, 8, 2, 2, 2, 3, 3, 3, 17, 2, 5, 6, 6, 6
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,4
|
|
COMMENTS
|
"Positions" are counted 0,1,2,3,... starting with the least significant digit.
|
|
LINKS
|
|
|
FORMULA
|
|
|
EXAMPLE
|
2^10 = 1024, the rightmost zero is in position 2, so a(10) = 2. Another example, 2^5 = 32, so we need to add a leading zero: 032, thus the rightmost zero will be in position 2, and a(5) = 2.
|
|
MAPLE
|
A181611 := proc(n) local dgs, i ; dgs := convert(2^n, base, 10) ; i := ListTools[Search](0, dgs) ; if i > 0 then i-1; else nops(dgs) ; end if ; end proc: # R. J. Mathar, Jan 30 2011
a:= proc(n) local m, i;
m:= 2^n;
for i from 0 while m>0 and irem(m, 10, 'm')<>0
do od; i
end:
|
|
MATHEMATICA
|
Table[Position[Reverse[Prepend[IntegerDigits[2^n], 0]],
0][[1]][[1]] - 1, {n, 121}]
|
|
PROG
|
(PARI) a(n) = {my(d = Vecrev(digits(2^n))); for (i=1, #d, if (!d[i], return (i-1)); ); #d; } \\ Michel Marcus, Jan 01 2016
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,base
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|