A080212 Binomial(n, smallest odd prime factor of n).

1, 2, 1, 4, 1, 20, 1, 8, 84, 252, 1, 220, 1, 3432, 455, 16, 1, 816, 1, 15504, 1330, 705432, 1, 2024, 53130, 10400600, 2925, 1184040, 1, 4060, 1, 32, 5456, 2333606220, 324632, 7140, 1, 35345263800, 9139, 658008, 1, 11480, 1, 7669339132, 14190

Offset: 1

Author

Reinhard Zumkeller, Feb 06 2003

Keywords

• nonn

Comments

For n>1: a(n)=1 iff n is prime.

Crossrefs

Cf. A078701, A080211, A080213.