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A375153
Decimal expansion of the sagitta of a regular 9-gon with unit side length.
9
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
OFFSET
-1,1
LINKS
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).
Sequence in context: A296496 A065465 A265308 * A377303 A319858 A351210
KEYWORD
nonn,cons,easy
AUTHOR
Paolo Xausa, Aug 01 2024
STATUS
approved