A075857 Least common multiple of totient and cototient of n.

0, 1, 2, 2, 4, 4, 6, 4, 6, 12, 10, 8, 12, 24, 56, 8, 16, 12, 18, 24, 36, 60, 22, 16, 20, 84, 18, 48, 28, 88, 30, 16, 260, 144, 264, 24, 36, 180, 120, 48, 40, 60, 42, 120, 168, 264, 46, 32, 42, 60, 608, 168, 52, 36, 120, 96, 252, 420, 58, 176, 60, 480, 108, 32, 816, 460, 66

Offset

1,3

Links

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

Formula

a(n) = A000010(n)*A051953(n)/A009195(n).

Mathematica

Table[LCM[EulerPhi[n], (n-EulerPhi[n])], {n, 70}] (* Harvey P. Dale, Jun 10 2019 *)

Prog

(PARI) a(n) = {my(p = eulerphi(n)); lcm(p, n-p); } \\ Amiram Eldar, Nov 30 2024

Crossrefs

Cf. A000010, A009195, A051953.

Sequence in context: A153835 A338098 A171462 * A023817 A300754 A145392

Adjacent sequences: A075854 A075855 A075856 * A075858 A075859 A075860

Keyword

nonn

Author

Reinhard Zumkeller, Oct 15 2002

Status

approved