A334848 Decimal expansion of circumference of x^2 + 9 y^2 = 9.

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

Offset

1,2

Links

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

Formula

arclength = 4 E(-8), where E = complete elliptic integral.

Example

arclength = 13.3648932205552582301295023250601962394009826...

Mathematica

s = Integrate[Sqrt[D[ 3 Cos[t], t]^2 + D[Sin[t], t]^2], {t, 0, 2 Pi}]
r = N[s, 200]
RealDigits[r][[1]]

Crossrefs

Cf. A333202, A334849.

Sequence in context: A199153 A182627 A135986 * A284614 A349392 A069734

Adjacent sequences: A334845 A334846 A334847 * A334849 A334850 A334851

Keyword

nonn,cons,easy

Author

Clark Kimberling, Jun 15 2020

Status

approved