A085769 Total number of zeros in the decimal expansions of 2^n and 5^n.

0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1, 2, 2, 1, 1, 1, 1, 0, 1, 2, 2, 2, 3, 2, 1, 2, 2, 2, 3, 1, 1, 2, 0, 3, 3, 2, 2, 4, 3, 5, 2, 3, 4, 5, 8, 5, 5, 6, 4, 4, 4, 8, 9, 5, 7, 4, 3, 1, 5, 6, 8, 8, 9, 10, 7, 7, 5, 8, 11, 11, 7, 8, 5, 4, 4, 6, 5, 6, 8, 10, 7, 6, 7, 4, 2, 4, 9, 9, 7, 9, 9, 8, 10, 10, 5, 5, 8, 11, 14, 18

Offset

1,12

Comments

10^33 is believed to be the largest power of 10 that can be expressed as the product of 2 numbers which contain no zero digits.

References

C. Stanley Ogilvy and John T. Anderson, Excursions in Number Theory. Dover. New York: 1988. Page 89.

C. Pickover, Wonders of Numbers, Oxford University Press, NY, 2001, pp. 201-202, 353.

Links

Table of n, a(n) for n=1..100.

C. A. Pickover, "Wonders of Numbers, Adventures in Mathematics, Mind and Meaning," Zentralblatt review

Example

a(58)=1 because 10^58 = 288230376151711744 * 34694469519536141888238489627838134765625
and the latter two numbers contain only one zero between them.

Crossrefs

Sequence in context: A334091 A054535 A054534 * A237422 A102552 A131341

Adjacent sequences: A085766 A085767 A085768 * A085770 A085771 A085772

Keyword

nonn,base

Author

Jason Earls, Jul 22 2003

Status

approved