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A096549
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Least exponent k such that the lowest n digits in the decimal representation of 2^k are even.
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0
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1, 6, 10, 11, 19, 43, 50, 50, 71, 71, 523, 590, 590, 12106, 12106, 12106, 12106, 56590, 505206, 1570511, 1570511, 4033966, 4033966, 9525771, 24045606, 24045606, 57862019, 183002599, 183002599, 877875719, 877875719, 877875719, 3789535319
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| This problem was discussed in a thread "Power of 2 with all even digits?" in the newsgroup sci.math (date Jun 25, 2004) with contributions from Edwin Clark, James Waldby, Bertram Felgenhauer, Richard Tobin, Oskar Lanzi III and others.
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LINKS
| Newsgroup sci.math, Power of 2 with all even digits?
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EXAMPLE
| a(5)=19 because 2^19=524288 is the smallest power of 2 that has a decimal representation ending in 5 even digits.
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CROSSREFS
| Cf. A000079.
Sequence in context: A132628 A039509 A068442 * A136812 A109397 A133210
Adjacent sequences: A096546 A096547 A096548 * A096550 A096551 A096552
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KEYWORD
| base,nonn
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AUTHOR
| Hugo Pfoertner (hugo(AT)pfoertner.org), Jul 07 2004
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EXTENSIONS
| a(21)...a(35) from Richard Tobin (richard(AT)cogsci.ed.ac.uk) Jun 29, 2004.
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