A388515 Decimal expansion of 4 * exp(-Pi / 2).

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

Offset

0,1

Links

Table of n, a(n) for n=0..86.

Simon Plouffe, Numbers in the base e^Pi, 2025.

Formula

Empirical: Equals Sum_{k>=0} A112143(k) / exp(k*Pi).

Example

0.83151830540304763418782247933991508014...

Mathematica

First[RealDigits[4*Exp[-1/2*Pi], 10, 100]]

Prog

(PARI) 4 * exp(-Pi / 2)

Crossrefs

Cf. A112143.

Sequence in context: A021550 A388087 A388470 * A092555 A001061 A259073

Adjacent sequences: A388512 A388513 A388514 * A388516 A388517 A388518

Keyword

nonn,cons

Author

Simon Plouffe, Sep 17 2025

Status

approved