1,2

a(n) is nonzero for all n up to 10^4. Is it always so?

Table of n, a(n) for n=1..68.

9 differs by 2 from the nearest prime, but 9 * 2 = 18 differs only by 1; hence a(9) = 18.

Sequence in context: A200447 A274840 A205406 * A204928 A171723 A039050

Adjacent sequences: A066756 A066757 A066758 * A066760 A066761 A066762

nonn

Joseph L. Pe, Jan 17 2002

approved