1,2

Table of n, a(n) for n=1..64.

a(n) = 2*A007917(n) for n>2. - Andrey Zabolotskiy, Aug 16 2016

a(2) = 3 because phi(3!) is divisible by 2!.

(PARI) a(n) = {my(k = 1); while(eulerphi(k!) % n!, k++); k; }

Cf. A048855, A007917.

Sequence in context: A111652 A159787 A184161 * A316563 A316140 A147849

Adjacent sequences: A275997 A275998 A275999 * A276001 A276002 A276003

nonn

Altug Alkan, Aug 16 2016

approved