1,1

9 primes below 24 = {2,3,5,7,11,13,17,19,23}; RRS[24]={1,5,7,11,13,17,19,23}, so 24 is here.

Do[s=EulerPhi[n]-PrimePi[n]; If[Equal[s, -1], Print[n]], {n, 1, 10000}]

Cf. A037228, A037171, A000010, A000720.

Adjacent sequences: A073452 A073453 A073454 this_sequence A073456 A073457 A073458

Sequence in context: A033845 A120942 A031478 this_sequence A020333 A044831 A033003

fini,full,nonn

Labos E. (labos(AT)ana.sote.hu), Aug 02 2002