A372912 Decimal expansion of (2/7)*sqrt(3).

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

Offset

0,1

Links

Table of n, a(n) for n=0..85.

Formula

Equals Sum_{k>=0} tan(k*Pi/3)/2^k.

Example

0.494871659305393512436413240430249247697944358...

Mathematica

s = Sum[Tan[k Pi/3]/2^k, {k, 0, Infinity}]
d = N[s, 100]
First[RealDigits[d]]
N[(2 Sqrt[3])/7, 100]

Prog

(Python)
from math import isqrt
def A372912(n): return isqrt(12*10**(n+1<<1)//49)%10 # Chai Wah Wu, Jul 08 2024

Crossrefs

Cf. A372913, A372914.

Sequence in context: A271948 A068950 A021673 * A224299 A141653 A336051

Adjacent sequences: A372909 A372910 A372911 * A372913 A372914 A372915

Keyword

nonn,cons

Author

Clark Kimberling, Jul 01 2024

Status

approved