A387444 Decimal expansion of cos(Pi/23).

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

Offset

0,1

Links

Paolo Xausa, Table of n, a(n) for n = 0..10000

R. J. Mathar, Reduction formulas of the cosine of integer fractions of pi, (2008) vixra:2210.0026.

Index entries for algebraic numbers, degree 11

Formula

Equals sin(21*Pi/46).

Largest of the 11 real-valued roots of 2048*x^11 -1024*x^10 -5120*x^9 +2304*x^8 +4608*x^7 -1792*x^6 -1792*x^5 +560*x^4 +280*x^3 -60*x^2 -12*x +1 = 0.

Example

0.99068594603633075234232296009620600513999918345482...

Mathematica

First[RealDigits[Cos[Pi/23], 10, 100]] (* Paolo Xausa, Nov 17 2025 *)

Crossrefs

Cf. A019690.

Sequence in context: A199960 A385535 A257176 * A324859 A377694 A090655

Adjacent sequences: A387441 A387442 A387443 * A387445 A387446 A387447

Keyword

nonn,cons,easy

Author

R. J. Mathar, Aug 29 2025

Status

approved