OFFSET
1,3
COMMENTS
Decimal expansion of sum sigma_1 involved in calculation of i^i. [Uhler]
LINKS
Robert G. Wilson v, Table of n, a(n) for n = 1..1000
H. S. Uhler, On the numerical value of i^i, Amer. Math. Monthly, 28 (1921), 114-116.
EXAMPLE
1.1402383210764287921411319803793508907668976675113205505775099696012133160034...
MATHEMATICA
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, 0, 421, 2}], 10, 111][[1]] (* Robert G. Wilson v, Feb 16 2019 *)
RealDigits[Cosh[Pi/6], 10, 120][[1]] (* Vaclav Kotesovec, Feb 16 2019 *)
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
N. J. A. Sloane, Feb 11 2019
EXTENSIONS
More digits from Robert G. Wilson v, Feb 16 2019
Simpler definition from Vaclav Kotesovec, Feb 16 2019
STATUS
approved