A388180 - OEIS

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A388180

Decimal expansion of 18 * exp(-Pi / 2) * sqrt(2).

1

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

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..87.

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

FORMULA

Empirical: Equals Sum_{k>=0} A007247(k) / exp(k*Pi).

EXAMPLE

5.2917500918811744141042643711656486197...

MATHEMATICA

First[RealDigits[18*Sqrt[2]*Exp[-1/2*Pi], 10, 100]]

PROG

(PARI) 18 * exp(-Pi / 2) * sqrt(2)

CROSSREFS

Sequence in context: A248751 A021193 A010483 * A003671 A318379 A065262

Adjacent sequences: A388177 A388178 A388179 * A388181 A388182 A388183

KEYWORD

nonn,cons

AUTHOR

Simon Plouffe, Sep 15 2025

STATUS

approved