A388551 Decimal expansion of sqrt((2 * (2+sqrt(5))) / 5) * exp(-Pi/12).

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

Offset

1,5

Links

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

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

Index entries for transcendental numbers.

Formula

Empirical: Equals Sum_{k>=0} A113298(k) / exp(k*Pi).

Example

1.00187473898304091393157819677536014306183001939286450451416200813528002424....

Mathematica

First[RealDigits[Sqrt[(2*(2 + Sqrt[5]))/5]*Exp[-1/12*Pi], 10, 100]]

Prog

(PARI) (16/125) * exp(-1/12 * Pi) * 2^(1/10) * 5^(1/4) * gamma(9/10)^3 * gamma(7/10)^3 * (5+5^(1/2))^3 * (1/4*5^(1/2)-1/4)^3 * (1/4*5^(1/2)+1/4)^3 / gamma(4/5)^6

Crossrefs

Cf. A113298.

Sequence in context: A070482 A070702 A019870 * A395391 A019903 A327340

Adjacent sequences: A388548 A388549 A388550 * A388552 A388553 A388554

Keyword

nonn,cons

Author

Simon Plouffe, Sep 18 2025

Status

approved