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A049514
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Starting index of a string of 2 or more consecutive equal digits in decimal expansion of Pi.
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14
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25, 35, 45, 60, 80, 95, 118, 126, 131, 136, 154, 155, 175, 178, 179, 183, 186, 202, 205, 212, 216, 218, 231, 258, 277, 283, 308, 310, 316, 318, 323, 361, 363, 365, 373, 378, 396, 402, 428, 438, 446, 454, 460, 473, 485, 495, 504, 508, 512, 517, 536, 560, 593
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OFFSET
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1,1
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COMMENTS
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Digits 3,1,4,... are indexed 1,2,3,...
See A049518 for the "exactly 2" variant, which differs from a(11) on. - M. F. Hasler, Oct 18 2019
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LINKS
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EXAMPLE
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The integer part of Pi*10^25 ends in 33, i.e., at position 25 starts the (first) string of two repeated digits 3, therefore a(1) = 25.
At position 154 starts a string of three '1's, so this sequence lists both, 154 and 155, but sequence A049518 lists none of these. (End)
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MATHEMATICA
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ConsecutiveOccurrences1[alist_, n_] := Flatten @ Position[ Apply[ SameQ, Partition[ alist, n, 1], {1}], True]; ConsecutiveOccurrences1[ First[ RealDigits[Pi, 10, 601]], 2]
Flatten[Position[Partition[RealDigits[Pi, 10, 1000][[1]], 2, 1], _?(#[[1]] == #[[2]]&), {1}, Heads->False]] (* Harvey P. Dale, Dec 21 2014 *)
SequencePosition[RealDigits[Pi, 10, 1000][[1]], {x_, x_}][[All, 1]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Mar 30 2019 *)
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PROG
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(Haskell)
a049514 n = a049514_list !! (n-1)
a049514_list = filter ((== 0) . a095916) [1..]
(PARI) A049514_upto(N=999)={default(realprecision, N); my(p=digits(Pi\10^-N)); select(i->p[i]==p[i+1], [9..N-1])} \\ M. F. Hasler, Oct 18 2019
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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