OFFSET
0,2
LINKS
EXAMPLE
a(7) = 42 = 7*6 has decreasing even digits.
For n = 25, the conditions require that the desired multiple 25k have k even, i.e., 25k = 25(2i) = 50i = (5i)(10). Thus the final digit is 0, so the next-to-last digit must be 2, but this is impossible since 5i always ends in 0 or 5. Thus a(25) = -1. - John W. Layman, Nov 01 2001
CROSSREFS
KEYWORD
base,easy,nice,sign
AUTHOR
Amarnath Murthy, Jun 28 2001
EXTENSIONS
More terms and better description from John W. Layman, Nov 01 2001
Further terms from Jud McCranie, Nov 01 2001
STATUS
approved