A375153 - OEIS

A375153

Decimal expansion of the sagitta of a regular 9-gon with unit side length.

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

(list; constant; graph; refs; listen; history; text; internal format)

OFFSET

-1,1

LINKS

Paolo Xausa, Table of n, a(n) for n = -1..10000

Eric Weisstein's World of Mathematics, Regular Polygon.

Eric Weisstein's World of Mathematics, Sagitta

FORMULA

Equals tan(Pi/18)/2 = A019908/2.

Equals A375151 - A375152.

Equals sqrt(1/4 + A199590). - Hugo Pfoertner, Aug 01 2024

EXAMPLE

0.088163490354232486735545193434309493060816531174...

MATHEMATICA

First[RealDigits[Tan[Pi/18]/2, 10, 100]]

CROSSREFS

Cf. A375151 (circumradius), A375152 (apothem), A256853 (area).

Cf. sagitta of other polygons with unit side length: A020769 (triangle), A174968 (square), A375068 (pentagon), A375069 (hexagon), A374972 (heptagon), A375070 (octagon), A375189 (10-gon), A375192 (11-gon), A375194 (12-gon).

Cf. A019908, A199590.

Sequence in context: A296496 A065465 A265308 * A377303 A319858 A351210

Adjacent sequences: A375150 A375151 A375152 * A375154 A375155 A375156

KEYWORD

nonn,cons,easy

AUTHOR

Paolo Xausa, Aug 01 2024

STATUS

approved