A227530 Integer lengths of the n-th Copeland-Erdős prime (concatenation of the first n entries (digits) of A033308 is prime).

1, 2, 4, 11, 353, 355, 499, 1171, 1543, 5719, 11048, 68433, 97855, 292447

Offset

1,2

Comments

a(15) > 300000. - Eric W. Weisstein (according to Mark Rodenkirch as of Dec 13 2015)

The larger of these are probable primes.

a(15) > 5*10^5 according to Mark Rodenkirch, June 2016. - M. F. Hasler, Apr 24 2017

Links

Table of n, a(n) for n=1..14.

Mark Rodenkirch (a.k.a. "rogue"), Copeland-Erdos Constant Primes, MersenneForum.org, June 2016.

Eric Weisstein's World of Mathematics, Copeland-Erdős Constant Digits

Crossrefs

Cf. A227529 (primes corresponding to a(n) digits of the Copeland-Erdős constant), A019518, A069151.

Cf. also A033308 (Decimal expansion of Copeland-Erdős constant: concatenate primes).

Sequence in context: A038093 A057284 A156463 * A218129 A156519 A215795

Adjacent sequences: A227527 A227528 A227529 * A227531 A227532 A227533

Keyword

nonn,hard,base

Author

Eric W. Weisstein, Jul 14 2013

Extensions

a(12) = 68433 from Eric W. Weisstein, Aug 17 2013

a(13) = 97855 from Eric W. Weisstein, Oct 24 2015

a(14) = 292447 from Eric W. Weisstein, Dec 17 2015

Status

approved