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Search: id:A068987
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| A068987 |
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a(n) = first position in the digit sequence 3,1,4,1,5,9,.... of pi where the pattern "1,2,...,n" occurs. |
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+0
2
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| 2, 149, 1925, 13808, 49703, 2458886, 9470345, 186557267
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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1. We may never know if a(n) is defined for all n. 2. We split up the digits of any number > 9 in the pattern, e.g. if n = 11, we search for the pattern "1,2,3,4,5,6,7,8,9,1,0,1,1". 3. The pattern "1,2,3,4,5,6" does not occur before the 100,000-th term in the digit sequence of Pi.
Here are two more terms: a(6) and a(7) were found via the referenced Pi-Search link, through which 100 million digits of pi are currently available. - Rick L. Shepherd (rshepherd2(AT)hotmail.com), Oct 10 2002
200 million digits now available at Pi-Search page. - Rick L. Shepherd (rshepherd2(AT)hotmail.com), Aug 06 2006
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LINKS
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D. G. Andersen, The Pi-Search Page
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MATHEMATICA
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p = ToString[N[Pi, 50000]/10]; t = {1, 12, 123, 1234, 12345}; g[n_] := StringPosition[p, ToString[n]][[1]][[1]] - 2; Table[g[t[[i]]], {i, 1, 5}]
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CROSSREFS
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Sequence in context: A110624 A062596 A142415 this_sequence A128350 A046473 A024245
Adjacent sequences: A068984 A068985 A068986 this_sequence A068988 A068989 A068990
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KEYWORD
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nonn,base
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AUTHOR
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Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Apr 01 2002
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EXTENSIONS
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More terms from Rick L. Shepherd (rshepherd2(AT)hotmail.com), Oct 10 2002
a(8) from Rick L. Shepherd (rshepherd2(AT)hotmail.com), Aug 06 2006
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