A062948 - OEIS

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

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,3

LINKS

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

PROG

(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

CROSSREFS

Cf. A023022, A002808.

Sequence in context: A303539 A303540 A137266 * A365159 A358639 A358640