OFFSET
1,2
COMMENTS
a(n) is nonzero for all n up to 10^4. Is it always so?
EXAMPLE
9 differs by 2 from the nearest prime, but 9 * 2 = 18 differs only by 1; hence a(9) = 18.
CROSSREFS
KEYWORD
nonn
AUTHOR
Joseph L. Pe, Jan 17 2002
STATUS
approved