A073455 Numbers n such that to phi(n) = pi(n)-1.

6, 12, 18, 24, 42, 60

Offset

1,1

Links

Table of n, a(n) for n=1..6.

Example

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.

Mathematica

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

Crossrefs

Cf. A037228, A037171, A000010, A000720.

Sequence in context: A147306 A359957 A031478 * A279894 A209309 A020333

Adjacent sequences: A073452 A073453 A073454 * A073456 A073457 A073458

Keyword

fini,full,nonn

Author

Labos Elemer, Aug 02 2002

Status

approved