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 A228807 a(n) = phi( a(n-1) + a(n-2) + 1) with a(0) = 0 and a(1) = 1. 1
 0, 1, 1, 2, 2, 4, 6, 10, 16, 18, 24, 42, 66, 108, 120, 228, 348, 576, 720, 1296, 2016, 3312, 5256, 7200, 12456, 17860, 25200, 40256, 37368, 39600, 72900, 112500, 185400, 282204, 364800, 517600, 805392, 1133988, 1939380, 2788176, 4727556, 6819120 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 COMMENTS Difference between A000045 & A228807: 0, 0, 0, 0, 1, 1, 2, 3, 5, 16, 31, 47, 78, 125, 257, 382, 639, 1021, 1864, 2885, 4749, 7634, ... . LINKS Mihai Caragiu and Robert G. Wilson v, Table of n, a(n) for n = 0..500 Mihai Caragiu, Mathematical Trips. Mihai Caragiu and Ashley Risch, An Euler-Fibonacci Sequence, Far East Journal of Mathematical Sciences 52 (1), 1 - 7 (May 2011) FORMULA a(n) = phi( a(n-1) + a(n-2) + 1) with a(0) = 0 & a(1) = 1. MATHEMATICA a[0] = 0; a[1] = 1; a[n_] := a[n] = EulerPhi[a[n - 1] + a[n - 2] + 1]; Array[a, 50, 0] RecurrenceTable[{a[0]==0, a[1]==1, a[n]==EulerPhi[a[n-1]+a[n-2]+1]}, a, {n, 50}] (* Harvey P. Dale, Feb 16 2014 *) CROSSREFS Cf. A000010, A000045. Sequence in context: A192682 A050194 A288006 * A262258 A293633 A006355 Adjacent sequences: A228804 A228805 A228806 * A228808 A228809 A228810 KEYWORD nonn AUTHOR Mihai Caragiu and Robert G. Wilson v, Sep 04 2013 STATUS approved

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Last modified December 1 17:35 EST 2023. Contains 367500 sequences. (Running on oeis4.)