A362485 Number of numbers k such that iphi(k) = n, where iphi is the infinitary totient function A091732.

2, 2, 2, 2, 0, 4, 0, 4, 0, 2, 0, 6, 0, 0, 2, 4, 0, 4, 0, 2, 0, 2, 0, 10, 0, 0, 0, 2, 0, 6, 0, 4, 0, 0, 0, 8, 0, 0, 0, 4, 0, 2, 0, 2, 2, 2, 0, 14, 0, 0, 0, 2, 0, 2, 0, 2, 0, 2, 0, 10, 0, 0, 0, 4, 0, 4, 0, 0, 0, 2, 0, 14, 0, 0, 0, 0, 0, 2, 0, 8, 0, 2, 0, 4, 0, 0

Offset

1,1

Comments

a(n) is even for all n, because if k is a solution to iphi(k) = n, and A007814(k) is even, then 2*k is also a solution, i.e., iphi(2*k) = n.

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Formula

a(A362486(n)) = 0.

Mathematica

a[n_] := Length[invIPhi[n]]; Array[a, 100] (* using the function invIPhi from A362484 *)

Crossrefs

Row lengths of A362484.

Cf. A007814, A091732, A362486 (positions of 0's), A362487 (indices of records).

Similar sequences: A014197, A063740, A361967, A362181.

Sequence in context: A333180 A127444 A241477 * A268243 A159782 A268242

Adjacent sequences: A362482 A362483 A362484 * A362486 A362487 A362488

Keyword

nonn

Author

Amiram Eldar, Apr 22 2023

Status

approved