A388455 Decimal expansion of sqrt(4-2 * sqrt(2)).

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

Offset

1,3

Links

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

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

Index entries for algebraic numbers, degree 4.

Formula

Empirical: Equals Sum_{k>=0} A080015(k) / exp(k*Pi).

Minimal polynomial x^4-8*x^2+8. - R. J. Mathar, Jun 03 2026

This^2 = A388622. - R. J. Mathar, Jun 03 2026

Example

1.0823922002923939687994464107327788401...

Mathematica

First[RealDigits[Sqrt[4 - 2*Sqrt[2]], 10, 100]]

Prog

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

Crossrefs

Cf. A080015.

Sequence in context: A388868 A254268 A388817 * A247684 A248304 A248303

Adjacent sequences: A388452 A388453 A388454 * A388456 A388457 A388458

Keyword

nonn,cons,changed

Author

Simon Plouffe, Sep 17 2025

Status

approved