A388753 Decimal expansion of sqrt(2 * (-1+sqrt(2))).

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

Offset

0,1

Links

Paolo Xausa, Table of n, a(n) for n = 0..10000

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

Index entries for algebraic numbers, degree 4.

Formula

Empirical: Equals Sum_{k>=0} A210030(k) / exp(k*Pi).

Minimal polynomial: x^4 + 4*x^2 - 4. - Amiram Eldar, May 31 2026

Example

0.91017972112445468260871551564493713924...

Mathematica

First[RealDigits[Sqrt[2*(-1 + Sqrt[2])], 10, 100]]

Prog

(PARI) 2^(1/4) * (2-2^(1/2))^(1/2)

Crossrefs

Cf. A210030.

Sequence in context: A388816 A388468 A388863 * A269948 A121935 A070060

Adjacent sequences: A388750 A388751 A388752 * A388754 A388755 A388756

Keyword

nonn,cons,easy,changed

Author

Simon Plouffe, Sep 18 2025

Status

approved