login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A359104
Decimal expansion of the area enclosed by Sylvester's Bicorn curve.
0
7, 4, 6, 4, 5, 5, 9, 4, 5, 4, 3, 9, 3, 4, 6, 4, 6, 3, 3, 4, 1, 4, 6, 1, 6, 7, 2, 7, 5, 8, 9, 6, 5, 7, 5, 8, 7, 7, 0, 5, 3, 5, 3, 7, 5, 1, 0, 7, 8, 9, 6, 8, 2, 0, 3, 4, 3, 6, 5, 7, 6, 3, 5, 4, 3, 9, 6, 2, 3, 2, 4, 1, 4, 4, 5, 7, 8, 1, 1, 5, 1, 2, 9, 3, 6, 8, 6, 3, 8, 3, 3, 1, 3, 9, 0, 9, 0, 8, 9
OFFSET
0,1
COMMENTS
The Cartesian equation of Sylvester's Bicorn curve is y^2*(m^2-x^2) = (x^2+2*m*y-m^2)^2, here with parameter m=1. The area is proportional to the square m^2 of parameter m.
Corresponding arc length is given by A228764.
REFERENCES
M. Protat, Des Olympiades à l'Agrégation, Encadrement du bicorne, Problème 66, pp. 142-145, Ellipses, Paris 1997.
LINKS
Robert Ferréol, Bicorn, Mathcurve.
Eric Weisstein's World of Mathematics, Bicorn.
Wikipedia, Bicorn.
FORMULA
Equals (16*sqrt(3) - 27)*Pi/3.
EXAMPLE
0.746455945439346463341461672758965758770535375107896820343...
MAPLE
evalf((16*sqrt(3) - 27)*Pi/3, 100);
MATHEMATICA
RealDigits[(16*Sqrt[3] - 27)*Pi/3, 10, 120][[1]] (* Amiram Eldar, Dec 18 2022 *)
CROSSREFS
Cf. A228764 (length).
Other area of curves: A019692 (deltoid), A197723 (cardioid), A122952 (nephroid), A180434 (Newton strophoid).
Sequence in context: A021138 A336763 A195366 * A185196 A347909 A085665
KEYWORD
nonn,cons
AUTHOR
Bernard Schott, Dec 18 2022
STATUS
approved