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A107647 EulerPhi function applied to tribonacci numbers. 0
0, 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 (list; graph; refs; listen; history; internal format)
OFFSET

0,5

FORMULA

F[n]=F[n-1]+F[n-2]+F[n-3]; a(n) = EulerPhi[F[n]]

MATHEMATICA

F[1] = 0; F[2] = 1; F[3] = 1; F[n__] := F[n] = F[n - 1] + F[n - 2] + F[n - 3] a1 = Table[EulerPhi[F[n]], {n, 1, 50}]

CROSSREFS

Cf. A065449.

Sequence in context: A113540 A111658 A105692 * A145102 A145103 A009230

Adjacent sequences:  A107644 A107645 A107646 * A107648 A107649 A107650

KEYWORD

nonn

AUTHOR

Roger L. Bagula (rlbagulatftn(AT)yahoo.com), Jun 09 2005

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Last modified February 17 11:46 EST 2012. Contains 206011 sequences.