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A104958 Primes from merging of 2 successive digits in decimal expansion of cos(1). 2
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified April 16 04:49 EDT 2021. Contains 343030 sequences. (Running on oeis4.)