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A031140 Position of rightmost 0 in 2^n increases. 4
10, 20, 30, 40, 46, 68, 93, 95, 129, 176, 229, 700, 1757, 1958, 7931, 57356, 269518, 411658, 675531, 749254, 4400728, 18894561, 33250486, 58903708, 297751737, 325226398, 781717865, 18504580518, 27893737353, 103233492954 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

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

I.e., look for increasing number of nonzero digits after the rightmost digit '0'. - M. F. Hasler, Jun 21 2018

LINKS

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

Eric Weisstein's World of Mathematics, Zero.

EXAMPLE

From M. F. Hasler, Jun 21 2018: (Start)

2^10 = 1024 is the first power of 2 to have a digit '0', which is the third digit from the right, i.e., it has to its right no digit '0' and two nonzero digits.

2^20 = 1048576 is the next larger power with a digit '0' having to its right no digit '0' and more (namely 5) nonzero digits than the above 1024.

After 2^46 = 70368744177664 there is 2^52 = 4503599627370496 having a '0' further to the left, but this digit has another '0' to its right and therefore cannot be considered: The next term having more nonzero digits after its rightmost '0' is only 2^68. (End)

PROG

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

CROSSREFS

Cf. A031141, A031142, A031143.

Sequence in context: A069534 A237416 A236507 * A095973 A299970 A037997

Adjacent sequences:  A031137 A031138 A031139 * A031141 A031142 A031143

KEYWORD

nonn,base

AUTHOR

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

EXTENSIONS

More terms from Dan Hoey.

STATUS

approved

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Last modified December 17 00:28 EST 2018. Contains 318191 sequences. (Running on oeis4.)