%I #19 Feb 11 2025 14:22:03
%S 3,0,6,1,4,6,7,4,5,8,9,2,0,7,1,8,1,7,3,8,2,7,6,7,9,8,7,2,2,4,3,1,9,0,
%T 9,3,4,0,9,0,7,5,6,4,9,9,8,8,5,0,1,6,3,3,1,4,7,0,4,0,5,0,8,5,0,2,0,3,
%U 6,8,2,7,1,6,8,0,7,1,7,5,3,7,8,9,6,1,1,0,2,8,2,7,3,8,2,6,8,3,7,7,1,8,7,3,9
%N Decimal expansion of 8*sin(Pi/8).
%C Decimal expansion of the ratio of the perimeter of a regular 8-gon (octagon) to its diameter (largest diagonal).
%H <a href="/index/Al#algebraic_04">Index entries for algebraic numbers, degree 4</a>.
%F Equals 8*A182168.
%e 3.061467458920718173827679872243190934090756499885016331470405085020368271...
%p evalf(8*sin(Pi/8),100); # _Wesley Ivan Hurt_, Feb 01 2017
%t RealDigits[8*Sin[Pi/8], 10, 120][[1]] (* _Amiram Eldar_, Jun 26 2023 *)
%o (PARI) 8*sin(Pi/8)
%Y Cf. For other n-gons: A010466 (n=4), 10*A019827 (n=5, 10), A280533 (n=7), A280633 (n=9), A280725 (n=11), A280819 (n=12).
%Y Cf. A182168.
%K nonn,cons,changed
%O 1,1
%A _Rick L. Shepherd_, Jan 05 2017