A323983 - OEIS

%I #20 Feb 16 2019 12:05:35

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

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

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

%N Decimal expansion of sinh(Pi/6).

%C Decimal expansion of sum sigma_2 involved in calculation of i^i. [Uhler]

%H Robert G. Wilson v, <a href="/A323983/b323983.txt">Table of n, a(n) for n = 0..1000</a>

%H H. S. Uhler, <a href="http://www.jstor.org/stable/2972387">On the numerical value of i^i</a>, Amer. Math. Monthly, 28 (1921), 114-116.

%F A323982 + A323983 = A323984.

%e 0.5478534738880398084757156477174314033527835217758617619908956382877300771661...

%t a[0] = a[1] = 1; a[n_] := ((n - 2)^2 + 1) a[n - 2]; t[x_] := N[(1/2)^x*a[x]/x!, 128]; RealDigits[Sum[t[x], {x, 1, 421, 2}], 10, 111][[1]] (* _Robert G. Wilson v_, Feb 16 2019 *)

%t RealDigits[Sinh[Pi/6], 10, 120][[1]] (* _Vaclav Kotesovec_, Feb 16 2019 *)

%Y Cf. A323982, A323984, A323985, A323986, A323987.

%K nonn,cons

%O 0,1

%A _N. J. A. Sloane_, Feb 11 2019

%E More digits from _Robert G. Wilson v_, Feb 16 2019

%E Simpler definition from _Vaclav Kotesovec_, Feb 16 2019