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

23, 13, 97, 71, 17, 29, 97, 37, 73, 23, 31, 61, 17, 79, 67, 97, 53, 11, 47, 47, 71, 17, 17, 79, 71, 83, 89, 43, 71, 17, 73, 31, 11, 89, 97, 37, 41, 17, 73, 31, 47, 71, 17, 79, 97, 71, 11, 47, 47, 79, 23, 31, 11, 17, 79, 13, 43, 59, 43, 17, 67, 89, 59, 37, 73, 61, 43, 41, 17

Offset

1,1

Comments

Leading zeros are not permitted, i.e., all terms must be two digits in length. - Harvey P. Dale, Apr 20 2012

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

Links

Harvey P. Dale and Vincenzo Librandi, Table of n, a(n) for n = 1..1001

The first 15,000 digits of Cos(1) as calculated by Simon Plouffe at WorldWideSchool.org.

Eric Weisstein's World of Mathematics, Cosine Function

Mathematica

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

Crossrefs

Sequence in context: A070838 A199713 A064735 * A124601 A040508 A305943

Adjacent sequences: A104955 A104956 A104957 * A104959 A104960 A104961

Keyword

nonn,base

Author

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

Extensions

Offset changed from 0 to 1 by Vincenzo Librandi, Apr 28 2013

Status

approved