A356470 - OEIS

%I #20 Aug 21 2023 12:16:15

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

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

%U 0,7,4,9,1,8,6,7,7,0,7,2,3,8,0,1,7,2,8,6,2

%N Decimal expansion of (3 - sqrt(5))/(2*sqrt(2)).

%C Distance between points in the most spread-out hexagonal lattice such that the gap formed by any three mutually tangential unit disks contains a point inside or on its boundary.

%C Side-length of an equilateral triangle contained in a unit side-length equilateral triangle such that every vertex and midpoint of the smaller triangle is at distance 1/2 from the nearest vertex of the larger triangle.

%C A quartic number with denominator 2. Minimal polynomial is 4x^4 - 14x^2 + 1. - _Charles R Greathouse IV_, Sep 29 2022

%H Andrew Slattery, <a href="https://www.desmos.com/calculator/qxjlvsrvay">Interactive</a>

%H <a href="/index/Al#algebraic_04">Index entries for algebraic numbers, degree 4</a>

%e 0.2700907567377264536...

%t First[RealDigits[N[(3-Sqrt[5])/(2Sqrt[2]),89]]] (* _Stefano Spezia_, Aug 08 2022 *)

%o (PARI) (3-sqrt(5))/sqrt(8) \\ _Charles R Greathouse IV_, Sep 29 2022

%Y Cf. A002193.

%K nonn,cons

%O 0,1

%A _Andrew Slattery_, Aug 08 2022

%E More terms from _Stefano Spezia_, Aug 08 2022