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A374815
Decimal expansion of Sum_{k>=0} cos(4k*Pi/5)/2^k.
0
6, 8, 2, 1, 2, 5, 7, 4, 3, 0, 2, 4, 2, 0, 3, 7, 2, 4, 3, 6, 7, 2, 9, 8, 0, 4, 8, 2, 8, 7, 1, 9, 6, 3, 1, 1, 1, 8, 8, 3, 5, 7, 1, 7, 6, 1, 4, 7, 8, 2, 9, 4, 0, 0, 4, 3, 8, 5, 0, 4, 9, 7, 1, 9, 9, 6, 2, 6, 5, 1, 1, 6, 5, 0, 1, 3, 9, 6, 5, 3, 7, 1, 2, 5, 1, 0
OFFSET
0,1
FORMULA
Equals (49 - 3*sqrt(5))/62.
Equals Sum_{k>=0} cos(6 k*Pi/5)/2^k.
Minimal polynomial: 19 - 49 x + 31 x^2.
EXAMPLE
0.6821257430242037243672980482871963111...
MATHEMATICA
{b, m, h} = {2, 5, 4}; s = Sum[Cos[ h k Pi/m]/b^k, {k, 0, Infinity}]
d = N[s, 100]
First[RealDigits[d], 100]
CROSSREFS
Cf. A373021 (includes guide to related sequences).
Sequence in context: A372311 A246844 A246845 * A214369 A242769 A189090
KEYWORD
nonn,cons
AUTHOR
Clark Kimberling, Jul 20 2024
STATUS
approved