A373025 - OEIS

A373025

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

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

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OFFSET

1,2

LINKS

Table of n, a(n) for n=1..86.

FORMULA

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

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

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

EXAMPLE

1.3503729060226985949648873184633558...

MATHEMATICA