A107647 - OEIS

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

(list; graph; refs; listen; history; text; internal format)

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