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A002954
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Smallest number such that n-th iterate of Chowla function is 0.
(Formerly M1099)
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2
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2, 4, 8, 15, 12, 27, 24, 36, 90, 96, 245, 288, 368, 676, 1088, 2300, 1596, 1458, 3344, 3888, 5360, 8895, 11852, 25971, 23360, 38895, 35540, 35595, 36032, 53823, 47840, 62055, 59360, 83391, 70784, 128079, 145668, 349299, 254540, 327495, 293744, 328335, 167664
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OFFSET
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1,1
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COMMENTS
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Chowla's function (A048050) = sum of divisors of n except 1 and n.
a(83) > 10^10. - Donovan Johnson, Feb 15 2013
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REFERENCES
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M. Lal and A. Forbes, A note on Chowla's function, Math. Comp., 25 (1971), 923-925.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
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Donovan Johnson, Table of n, a(n) for n = 1..82
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MATHEMATICA
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chowla[n_] := DivisorSigma[1, n] - 1 - n; chowlaSeq[n_] := Module[{m = n, cnt = 0, seq = {}}, While[m > 0 && ! MemberQ[seq, m], AppendTo[seq, m]; m = chowla[m]; cnt++]; If[m == 0, AppendTo[seq, m]]; seq]; nn = 20; t = Table[0, {nn}]; left = nn; n = 1; While[left > 0, n++; cSeq = chowlaSeq[n]; c = Length[cSeq] - 1; If[cSeq[[-1]] == 0 && c <= nn && t[[c]] == 0, t[[c]] = n; left--]]; t (* T. D. Noe, Dec 29 2011 *)
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CROSSREFS
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Sequence in context: A118897 A098056 A097100 * A019278 A084345 A084561
Adjacent sequences: A002951 A002952 A002953 * A002955 A002956 A002957
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane.
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EXTENSIONS
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Terms 31 to 43 from T. D. Noe, Dec 29 2011
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STATUS
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approved
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