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A096549
Least exponent k such that the lowest n digits in the decimal representation of 2^k are even.
1
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
OFFSET
1,2
COMMENTS
This problem was discussed in a thread "Power of 2 with all even digits?" in the newsgroup sci.math (Jun 25 2004) with contributions from Edwin Clark, James Waldby, Bertram Felgenhauer, Richard Tobin, Oskar Lanzi III and others.
EXAMPLE
a(5)=19 because 2^19=524288 is the smallest power of 2 that has a decimal representation ending in 5 even digits.
CROSSREFS
Sequence in context: A039509 A277597 A068442 * A248757 A136812 A109397
KEYWORD
base,nonn
AUTHOR
Hugo Pfoertner, Jul 07 2004
EXTENSIONS
a(21) - a(35) from Richard Tobin (richard(AT)cogsci.ed.ac.uk), Jun 29 2004
STATUS
approved