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A104958 Primes from merging of 2 successive digits in decimal expansion of cos(1). 2


%S 23,13,97,71,17,29,97,37,73,23,31,61,17,79,67,97,53,11,47,47,71,17,17,

%T 79,71,83,89,43,71,17,73,31,11,89,97,37,41,17,73,31,47,71,17,79,97,71,

%U 11,47,47,79,23,31,11,17,79,13,43,59,43,17,67,89,59,37,73,61,43,41,17

%N Primes from merging of 2 successive digits in decimal expansion of cos(1).

%C Leading zeros are not permitted, i.e., all terms must be two digits in length. - _Harvey P. Dale_, Apr 20 2012

%C The last of the 21 2-digit primes to appear is a(233) = 19. - _Charles R Greathouse IV_, May 13 2019

%H Harvey P. Dale and Vincenzo Librandi, <a href="/A104958/b104958.txt">Table of n, a(n) for n = 1..1001</a>

%H The first <a href="http://www.worldwideschool.org/library/books/sci/math/MiscellaneousMathematicalConstants/chap14.html">15,000 digits of Cos(1)</a> as calculated by _Simon Plouffe_ at WorldWideSchool.org.

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/Cosine.html">Cosine Function</a>

%t Select[FromDigits/@Partition[RealDigits[Cos[1],10,400][[1]],2,1], PrimeQ[#]&&#>9&] (* _Harvey P. Dale_, Apr 20 2012 *)

%K nonn,base

%O 1,1

%A Andrew G. West (WestA(AT)wlu.edu), Mar 30 2005

%E Offset changed from 0 to 1 by _Vincenzo Librandi_, Apr 28 2013

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Last modified May 15 16:44 EDT 2021. Contains 343920 sequences. (Running on oeis4.)