A373025 - OEIS

%I #4 Jul 22 2024 15:28:11

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

%T 8,5,0,2,8,7,3,5,7,0,4,9,0,3,7,9,3,5,3,2,6,0,3,6,9,4,0,5,3,3,4,6,5,0,

%U 7,1,0,3,5,3,1,4,2,4,6,1,2,2,6,4,7,4

%N Decimal expansion of Sum_{k>=0} cos(k*Pi/5)/2^k.

%F Equals (23 + 3*sqrt(5))/22.

%F Equals Sum_{k>=0} cos(9 k*Pi/5)/2^k.

%F Minimal polynomial: 11 - 23 x + 11 x^2.

%e 1.3503729060226985949648873184633558...

%t {b, m, h} = {2, 5, 1}; s = Sum[Cos[ h  k  Pi/m]/b^k, {k, 0, Infinity}]

%t d = N[s, 100]

%t First[RealDigits[d], 100]

%Y Cf. A373021 (includes guide to related sequences).

%K nonn,cons

%O 1,2

%A _Clark Kimberling_, Jul 20 2024