A375070 - OEIS

%I #10 Aug 07 2024 06:13:11

%S 9,9,4,5,6,1,8,3,6,8,9,8,2,9,0,0,3,4,5,5,7,9,8,8,1,1,3,2,2,3,3,8,1,1,

%T 4,2,9,8,9,2,5,2,5,0,6,6,0,7,9,5,4,9,0,9,6,0,5,5,8,4,9,7,9,1,2,7,1,4,

%U 8,0,2,2,3,0,1,3,8,5,3,1,5,2,6,6,5,9,9,5,3,0

%N Decimal expansion of the sagitta of a regular octagon with unit side length.

%H Paolo Xausa, <a href="/A375070/b375070.txt">Table of n, a(n) for n = -1..10000</a>

%H Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/RegularPolygon.html">Regular Polygon</a>.

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

%F Equals tan(Pi/16)/2 = A343060/2.

%F Equals A285871 - A174968.

%e 0.09945618368982900345579881132233811429892525066...

%t First[RealDigits[Tan[Pi/16]/2, 10, 100]]

%Y Cf. A285871 (circumradius), A174968 (apothem), A090488 (area).

%Y Cf. sagitta of other polygons with unit side length: A020769 (triangle), A174968 (square), A375068 (pentagon), A375069 (hexagon), A374972 (heptagon), A375153 (9-gon), A375189 (10-gon), A375192 (11-gon), A375194 (12-gon).

%Y Cf. A343060.

%K nonn,cons,easy

%O -1,1

%A _Paolo Xausa_, Jul 30 2024