1,6

Table of n, a(n) for n=1..89.

Index entries for sequences related to primes in arithmetic progressions

a(2*n)=A000720(2*n)-1; a(n)=0 iff n=1 or n prime, a(A008578(n))=1. - Reinhard Zumkeller, Sep 11 2003

n=20, spf(20)=2: 8 primes of form 1+k*2: 1+1*2=3, 1+2*2=5,

1+3*2=7, 1+5*2=11, 1+6*2=13, 1+8*2=17 and 1+9*2=19, therefore a(20)=8;

n=21, spf(21)=3: 3 primes of form 1+k*3: 1+2*3=7, 1+4*3=13 and

1+6*3=19, therefore a(21)=3.

Cf. A035096.

Sequence in context: A199470 A098006 A336916 * A054875 A324115 A029239

Adjacent sequences: A082647 A082648 A082649 * A082651 A082652 A082653

nonn

Reinhard Zumkeller, May 16 2003

approved