OFFSET
1,2
COMMENTS
n=5: 10 = 1+9 = 3+7, we can see 4 different lucky numbers. so a(5) = 4.
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Naohiro Nomoto, Feb 25 2002
EXTENSIONS
More terms from Sean A. Irvine, Feb 08 2024
STATUS
approved