A107647 Euler's totient function applied to tribonacci numbers.

1, 1, 1, 2, 6, 12, 8, 20, 54, 148, 136, 144, 612, 1200, 1344, 2448, 10506, 16848, 13824, 22000, 83232, 148716, 205368, 377736, 920160, 1694088, 1880304, 3290112, 14839968, 22472640, 17805312, 42407136, 117876096, 327661128, 178588800, 561863168, 1604383200

Offset

2,4

Links

Amiram Eldar, Table of n, a(n) for n = 2..365

Formula

a(n) = A000010(A000073(n)). - Amiram Eldar, Mar 02 2020

Mathematica

F[1] = 0; F[2] = 1; F[3] = 1; F[n__] := F[n] = F[n - 1] + F[n - 2] + F[n - 3]; Table[EulerPhi[F[n]], {n, 2, 50}]

Crossrefs

Cf. A000010, A000073, A065449, A197218, A272040.

Sequence in context: A111658 A341664 A105692 * A210842 A245777 A245785

Adjacent sequences: A107644 A107645 A107646 * A107648 A107649 A107650

Keyword

nonn

Author

Roger L. Bagula, Jun 09 2005

Extensions

First term 0 removed and offset corrected by Amiram Eldar, Mar 02 2020

Status

approved