A321463 - OEIS

%I #12 Oct 02 2022 00:02:10

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

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

%U 1,3,9,0,6,2,6,3,0,3,5,2,3,9,5,0,6,0,9

%N Decimal expansion of 36*Pi.

%C Surface area and volume of a sphere of radius 3, the unique non-degenerate sphere with volume equal to surface area.

%C Let r be the radius of the sphere. Set (4/3)*Pi*r^3 = 4*Pi*r^2, then (4/3)*Pi*r = 4*Pi and r = 3. Thus, the volume V(3) = (4/3)*Pi*3^3 = 36*Pi and the surface area A(3) = 4*Pi*3^2 = 36*Pi.

%C In other words: 36*Pi is also the surface area of a sphere whose diameter equals the square root of 36. More generally x*Pi is also the surface area of a sphere whose diameter equals the square root of x. - _Omar E. Pol_, Nov 10 2018

%H <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>

%F Equals 36*A000796.

%e 113.097335529232556584655161798062103831098098377503809555098005323081390626....

%t First[RealDigits[N[36*Pi, 100], 10]] (* _Stefano Spezia_, Nov 10 2018 *)

%o (PARI) 36*Pi

%Y Cf. A000796.

%Y Cf. A019694 (surface area of sphere of radius 1), A019699 (volume of sphere of radius 1).

%K nonn,cons

%O 3,3

%A _Felix Fröhlich_, Nov 10 2018