# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a019987 Showing 1-1 of 1 %I A019987 #45 Apr 23 2024 05:16:22 %S A019987 5,7,2,8,9,9,6,1,6,3,0,7,5,9,4,2,4,6,8,7,2,7,8,1,4,7,5,3,7,1,1,2,5,7, %T A019987 7,9,8,0,2,1,7,5,2,2,2,3,5,1,4,3,9,2,6,4,7,2,5,8,1,1,0,3,6,0,6,5,2,9, %U A019987 2,2,8,9,3,6,4,7,9,1,9,3,0,6,7,2,4,1,6,2,8,2,2,0,6,8,3,8,8,0,6 %N A019987 Decimal expansion of tangent of 89 degrees. %C A019987 Also cotangent of 1 degree. - _Mohammad K. Azarian_, Jan 21 2006 %C A019987 An algebraic integer of degree 24. - _Charles R Greathouse IV_, Aug 27 2017 %C A019987 The least k > 0 such that floor(cot(1°)*10^k) is prime is k = 39. - _M. F. Hasler_, May 19 2023 %H A019987 Ivan Panchenko, Table of n, a(n) for n = 2..1000. %H A019987 Art of Problem Solving, USAMO 1996, Problem 1. %H A019987 Mohammad K. Azarian, Forty-Five Nested Equilateral Triangles and cosecant of 1 degree, Problem 813, College Mathematics Journal, Vol. 36, No. 5, November 2005, p. 413-414; Solution, College Mathematics Journal, Vol. 37, No. 5, November 2006, pp. 394-395. %H A019987 User ssaamil, I found a cool number I'd like to share, 57289961630759424687278147537112577980217. In reddit.com/r/math, May 12 2023 %H A019987 Index to sequences related to Olympiads. %H A019987 Index entries for algebraic numbers, degree 24 %F A019987 Equals (Sum_{k=1..90} 2*k*sin(2*k)) / 90, with k in degrees (link USAMO 1996). - _Bernard Schott_, Apr 30 2022 %e A019987 57.28996... %p A019987 evalf(cot(Pi/180),100); # _Bernard Schott_, Apr 30 2022 %t A019987 First[RealDigits[Cot[Pi/180], 10, 100]] (* _Paolo Xausa_, Apr 23 2024 *) %o A019987 (PARI) tan(89*Pi/180) \\ _Charles R Greathouse IV_, Aug 27 2017 %Y A019987 Cf. A073449, A019899-A019986 (same for 1, ..., 88 degrees). %K A019987 nonn,cons %O A019987 2,1 %A A019987 _N. J. A. Sloane_. %E A019987 Edited by _N. J. A. Sloane_, Aug 19 2008 at the suggestion of _R. J. Mathar_ # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE