|
%I #10 Aug 15 2015 14:51:51
%S 17,173,1732050807568877293
%N Theodorus-primes: primes formed from the concatenation of the initial decimal digits of Theodorus's constant, sqrt(3).
%C The next term (a(4)) has 111 digits. - _Harvey P. Dale_, Oct 24 2014
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/Theodorus-Prime.html">Theodorus-Prime</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/IntegerSequencePrimes.html">Integer Sequence Primes</a>
%e sqrt(3) = 1.732050807568877..., 17--the concatenation of the first 2 decimal digits--is prime, so a(1)=17.
%t nn=300;With[{ds3=RealDigits[Sqrt[3],10,nn][[1]]},Select[ Table[ FromDigits[ Take[ds3,n]],{n,nn}],PrimeQ]] (* _Harvey P. Dale_, Oct 24 2014 *)
%Y Cf. A119344.
%K nonn,bref,base
%O 1,1
%A _Eric W. Weisstein_, May 15 2006
%E Edited by _Charles R Greathouse IV_, Apr 27 2010
| 