A062948 a(n) = H(A002808(n)) where H(n) is the half-totient function, H(n) = phi(n)/2: (A023022) and A002808(n) are the composites.

1, 1, 2, 3, 2, 2, 3, 4, 4, 3, 4, 6, 5, 4, 10, 6, 9, 6, 4, 8, 10, 8, 12, 6, 9, 12, 8, 6, 10, 12, 11, 8, 21, 10, 16, 12, 9, 20, 12, 18, 14, 8, 15, 18, 16, 24, 10, 16, 22, 12, 12, 18, 20, 18, 30, 12, 16, 27, 20, 12, 32, 21, 28, 20, 12, 36, 22, 30, 23, 36, 16, 21, 30, 20, 16, 24, 24, 26

Offset: 1

Author

Jason Earls, Jul 21 2001

Keywords

• easy
• nonn

Links

• Harry J. Smith, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A023022, A002808.

Programs

PARI

H(n)=eulerphi(n)/2;
j=[]; for(n=2,200, if(isprime(n), n+1,j=concat(j,H(n) ))); j

PARI

{ n=0; for (m=2, 10^9, if (!isprime(m), write("b062948.txt", n++, " ", eulerphi(m)/2); if (n==1000, break)) ) } \\ Harry J. Smith, Aug 14 2009

Extensions

Offset changed from 2 to 1 by Harry J. Smith, Aug 14 2009