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Copeland-Erdős Constant Digits


The Copeland-Erdős constant has decimal expansion

 C=0.23571113...

(OEIS A033308).

The Earls sequence (starting position of n copies of the digit n) for e is given for n=1, 2, ... by 5, 113, 1181, 21670, 263423, 7815547, 35619942, ... (OEIS A224897).

The digit sequences 0123456789 and 9876543210 do not occur in the first 10^9 digits (E. Weisstein, Jul. 24, 2013).

C-constant primes occur at 1, 2, 4, 11, 353, 355, 499, 1171, 1543, 5719, 11048, 68433, 97855, 292447, ... (OEIS A227530) decimal digits. There are no others with fewer than 500000 decimal digits (Rodenkirch, Jun. 18, 2016).

The starting positions of the first occurrence of n=0, 1, 2, ... in the decimal expansion of C (not counting the initial 0 to the left of the decimal point) are 48, 5, 1, 2, 21, 3, 31, 4, 41, 12, ... (OEIS A229190).

Scanning the decimal expansion of C until all n-digit numbers have occurred, the last 1-, 2-, ... digit numbers appearing are 0, 84, 504, 8580, 07010, 088880, ... (OEIS A000000), which end at digits 48, 934, 24437, 366399, 4910479, 49672582, ... (OEIS A000000).

It is known that the Copeland-Erdős constant is normal in base 10 (Copeland and Erdős 1946), though the following table giving the counts of digits in the first 10^n terms, shows non-normal behavior up to at least 10^9 due arbitrarily cutting the digit string off in the middle of runs of primes with initial starting digits.

d\nOEIS1010010^310^410^510^610^710^810^9
0A0000000446575679975249790407812935983121745
1A000000433266230120468187375176660216794379161034016
2A0000001463731801684314876083901691491679602
3A000000216134125912015115987113451311201736110467722
4A0000000460685728676925796194820202683946253
5A0000001558674734676886794905816169183863547
6A0000000460667724776745794002815423283381734
7A000000216133122811889115336112905311107597109702515
8A0000000357654710776273791955814117383207903
9A000000011123122611827114910112628611090893109594963

See also

Constant Digit Scanning, Constant Primes, Copeland-Erdős Constant, Copeland-Erdős Constant Continued Fraction, Earls Sequence

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References

Copeland, A. H. and Erdős, P. "Note on Normal Numbers." Bull. Amer. Math. Soc. 52, 857-860, 1946.Rodenkirch, M. "Copeland-Erdos Constant Primes." May. 5, 2016. http://www.mersenneforum.org/showthread.php?p=433145#post433145.Sloane, N. J. A. Sequences A224897, A227530, and A229190 in "The On-Line Encyclopedia of Integer Sequences."

Cite this as:

Weisstein, Eric W. "Copeland-Erdős Constant Digits." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Copeland-ErdosConstantDigits.html

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