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A256854
Decimal expansion of area of a regular 11-gon with unit edge length.
11
9, 3, 6, 5, 6, 3, 9, 9, 0, 6, 9, 4, 5, 4, 3, 7, 5, 2, 4, 8, 8, 2, 3, 5, 8, 4, 5, 3, 2, 8, 4, 3, 3, 4, 2, 8, 7, 8, 8, 2, 5, 7, 4, 9, 6, 1, 8, 3, 5, 0, 2, 7, 3, 8, 7, 6, 8, 9, 3, 1, 8, 6, 6, 7, 9, 4, 7, 8, 7, 0, 9, 3, 9, 8, 2, 3, 1, 0, 0, 7, 6, 4, 6, 1, 3, 0, 1, 3, 6, 4, 4, 1, 0, 4, 8, 1, 1, 2, 3, 0, 8, 3, 1, 1, 0
OFFSET
1,1
FORMULA
Equals (p/4)*cot(Pi/p), with p = 11.
EXAMPLE
9.36563990694543752488235845328433428788257496183502738768931...
MATHEMATICA
RealDigits[11/4 Cot[Pi/11], 10, 120][[1]] (* Harvey P. Dale, Apr 03 2016 *)
PROG
(PARI) p=11; a=(p/4)*cotan(Pi/p) \\ Use realprecision in excess
CROSSREFS
Cf. A000796, A120011 (p=3), A102771 (p=5), A104956 (p=6), A178817 (p=7), A090488 (p=8), A256853 (p=9), A178816 (p=10), A178809 (p=12).
Sequence in context: A182547 A019737 A088543 * A182552 A021985 A309602
KEYWORD
nonn,cons
AUTHOR
Stanislav Sykora, Apr 12 2015
STATUS
approved