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URL: https://oeis.org/A178179

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A178179
Like A177904, but start with a(1)=0, a(2)=a(3)=1.
1
0, 1, 1, 2, 2, 5, 3, 5, 13, 7, 5, 5, 17, 3, 5, 5, 13, 23, 41, 11, 5, 19, 7, 31, 19, 19, 23, 61, 103, 17, 181, 43, 241, 31, 7, 31, 23, 61, 23, 107, 191, 107, 5, 101, 71, 59, 11, 47, 13, 71, 131, 43, 7, 181, 11, 199, 23, 233, 13, 269, 103, 11, 383, 71, 31, 97, 199, 109, 5, 313, 61, 379, 251, 691, 1321, 73, 139, 73, 19, 11, 103, 19, 19, 47, 17, 83, 7, 107, 197, 311, 41, 61, 59, 23, 13, 19, 11, 43, 73, 127, 3, 29, 53, 17, 11, 3, 31
OFFSET
1,4
COMMENTS
After 7 steps, enters a cycle of length 100. The complete cycle, ending at 31, is shown.
LINKS
Mihai Caragiu, Mathematical Trips.
Greg Back and Mihai Caragiu, The Greatest Prime Factor and Recurrent Sequences, Fibonacci Quart. 48 (2010), no. 4, 358-362.
MATHEMATICA
a[1] = 0; a[2] = a[3] = 1; a[n_] := a[n] = FactorInteger[a[n - 1] + a[n - 2] + a[n - 3]][[-1, 1]]; Array[a, 107] (* Robert G. Wilson v, Nov 17 2014 *)
nxt[{a_, b_, c_}]:={b, c, FactorInteger[a+b+c][[-1, 1]]}; NestList[nxt, {0, 1, 1}, 110][[All, 1]] (* Harvey P. Dale, Jul 17 2017 *)
CROSSREFS
Cf. A177904.
Sequence in context: A224166 A286109 A239665 * A284833 A321202 A308160
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Dec 19 2010
STATUS
approved