A274771 Number of primes <= n-th Carmichael lambda number.

0, 0, 1, 1, 2, 1, 3, 1, 3, 2, 4, 1, 5, 3, 2, 2, 6, 3, 7, 2, 3, 4, 8, 1, 8, 5, 7, 3, 9, 2, 10, 4, 4, 6, 5, 3, 11, 7, 5, 2, 12, 3, 13, 4, 5, 8, 14, 2, 13, 8, 6, 5, 15, 7, 8, 3, 7, 9, 16, 2, 17, 10, 3, 6, 5, 4, 18, 6, 8, 5, 19, 3, 20, 11, 8, 7, 10, 5, 21, 2

Offset: 1

Author

Vincenzo Librandi, Nov 11 2016

Keywords

• nonn

Crossrefs

Cf. A002322, A054782, A070804, A273974, A277062, A277063.

Programs

Magma

[0] cat [#PrimesUpTo(CarmichaelLambda(n)): n in [2..100]];

Maple

with(numtheory):
a:= n-> pi(lambda(n)):
seq(a(n), n=1..100);  # Alois P. Heinz, Nov 11 2016

Mathematica

Table[PrimePi[CarmichaelLambda[n]], {n, 100}]

Formula

a(n) = A000720(A002322(n)). - Michel Marcus, Nov 11 2016