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A229186 Beginning position of n in the decimal expansion of the Champernowne constant.

%I A229186 #14 Feb 16 2025 08:33:20
%S A229186 11,1,2,3,4,5,6,7,8,9,10,12,1,16,18,20,22,24,26,28,30,15,34,2,38,40,
%T A229186 42,44,46,48,50,17,37,56,3,60,62,64,66,68,70,19,39,59,78,4,82,84,86,
%U A229186 88,90,21,41,61,81,100,5,104,106,108,110,23
%N A229186 Beginning position of n in the decimal expansion of the Champernowne constant.
%C A229186 Ignoring the initial 0 to the left of the decimal point.
%C A229186 Same as A031297 but including the a(0) term.
%H A229186 Eric W. Weisstein, <a href="/A229186/b229186.txt">Table of n, a(n) for n = 0..999</a>
%H A229186 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ChampernowneConstantDigits.html">Champernowne Constant Digits</a>
%H A229186 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ConstantDigitScanning.html">Constant Digit Scanning</a>
%o A229186 (Python)
%o A229186 from itertools import count, islice
%o A229186 def agen():
%o A229186     k, chap = 1, ".1"
%o A229186     for n in count(0):
%o A229186         target = str(n)
%o A229186         while chap.find(target) == -1: k += 1; chap += str(k)
%o A229186         yield chap.find(target)
%o A229186 print(list(islice(agen(), 70))) # _Michael S. Branicky_, Oct 06 2022
%Y A229186 Cf. A033307 (decimal expansion of the Champernowne constant).
%Y A229186 Cf. A072290 (number of digits in the decimal expansion of the Champernowne constant that must be scanned to encounter all n-digit strings).
%Y A229186 Cf. A031297 (same sequence but omitting the a(0) term).
%K A229186 nonn,base,less
%O A229186 0,1
%A A229186 _Eric W. Weisstein_, Sep 15 2013