1,1

Next term if it exists is >= 10^8.

a(15) > 3*10^10. - Donovan Johnson

Table of n, a(n) for n=1..14.

phi(21)=12, 20=2^2*5^1, (2*5)+(2*1)=12.

Cf. A000010, A039696.

Sequence in context: A230656 A266950 A328689 * A246167 A000941 A000131

Adjacent sequences: A039774 A039775 A039776 * A039778 A039779 A039780

nonn,hard

Olivier Gérard

More terms from Jud McCranie

Corrected example and a(11)-a(14) from Donovan Johnson, Nov 14 2010

approved