

A227530


Integer lengths of the nth CopelandErdős prime (concatenation of the first n entries (digits) of A033308 is prime).


2



1, 2, 4, 11, 353, 355, 499, 1171, 1543, 5719, 11048, 68433, 97855, 292447
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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"), CopelandErdos Constant Primes, MersenneForum.org, June 2016.
Eric Weisstein's World of Mathematics, CopelandErdős Constant Digits


CROSSREFS

Cf. A227529 (primes corresponding to a(n) digits of the CopelandErdős constant), A019518, A069151.
Cf. also A033308 (Decimal expansion of CopelandErdős 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



