1,17

a(n) = A000720(n) - A156876(n).

R. Zumkeller, Table of n, a(n) for n = 1..10000

a(120)=#{13,17,19,31,37,43,61,67,71,73,79,97,10,103,109}=15.

A059500, A005384, A005385.

Sequence in context: A010096 A230864 A063510 * A214454 A140474 A091195

Adjacent sequences: A156875 A156876 A156877 * A156879 A156880 A156881

nonn

Reinhard Zumkeller, Feb 18 2009

approved