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Search: id:A136669
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| A136669 |
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A triangular sequence from a modulo-6 cyclic version of Jeffrey's halting function. |
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+0 2
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| 1, 1, 0, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0, 0, 1, 0, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1, 1
(list; table; graph; listen)
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OFFSET
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1,1
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COMMENT
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Row sums give A140087.
What is interesting here is that Richard Jeffery and Gregory Chaitin seem to reach completely different conclusions about the halting problem.
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REFERENCES
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G. J. Chaitin, Algorithmic Information Theory, Cambridge Univ. Press, 1987, page 169.
G. J. Chaitin, Meta Math, The Quest for Omega,Vintage Books,2005, page 29 ff.
Richard Jeffrey, Formal Logic: Its Scope and Limits. 3rd ed. McGraw Hill, 1990. ISBN 0-07-032357-7, pages 134-5
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FORMULA
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f(n_, 1) := n + 1; f[n_, 2] := Undecided; f[n_, 3] := If[n == 0, 0, n - 1]; f[n_, 4] := If[n == 0, Undecided, n - 1]; f[n_, 5] := 0; f[n_, 6] := Undecided; f[n_, m_] := f[n, 1 + Mod[m, 6]]; h(m,n)=If[ program halts/f(n,m) is decided,0,1]
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EXAMPLE
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{1},
{1, 0},
{1, 0, 1},
{1, 0, 1, 1},
{1, 0, 1, 1, 1},
{1, 0, 1, 1, 1, 0},
{1, 0, 1, 1, 1, 0, 0},
{1, 0, 1, 1, 1, 0, 0, 1},
{1, 0, 1, 1, 1, 0, 0, 1, 1},
{1, 0, 1, 1, 1, 0, 0, 1, 1, 1}
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MATHEMATICA
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(* use 10^50 as a symbol for " Undecided" or undefined.*) f[n_, 1] := n + 1; f[n_, 2] := 10^50; f[n_, 3] := If[n == 0, 0, n - 1]; f[n_, 4] := If[n == 0, 10^50, n - 1]; f[n_, 5] := 0; f[n_, 6] := 10^50; f[n_, m_] := f[n, 1 + Mod[m, 6]]; h[m_, n_] := If[f[n, m] == 10^50, 0, 1]; a = Table[Table[h[m, n], {m, 1, n}], {n, 1, 10}]; Flatten[a]
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CROSSREFS
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Cf. A124027, A072851.
Adjacent sequences: A136666 A136667 A136668 this_sequence A136670 A136671 A136672
Sequence in context: A108336 A118268 A143220 this_sequence A103842 A065535 A093719
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KEYWORD
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nonn,uned,tabl,more,obsc
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AUTHOR
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Roger L. Bagula (rlbagulatftn(AT)yahoo.com), Apr 03 2008
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EXTENSIONS
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The definition of this sequence is not clear to me. Furthermore, the rows appear to converge to a certain binary sequence. If so, there should be a cross-reference to it (or it should be added if it is not presently in the OEIS). - njas, Jun 04 2008
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