A388671 Decimal expansion of sqrt(2/5) * (3+sqrt(5))^(1/4).

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

Offset

0,1

Links

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

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

Index entries for algebraic numbers, degree 8.

Formula

Empirical: Equals Sum_{k>=0} A147702(k) / exp(k*Pi).

Minimal polynomial: 625*x^8 - 600*x^4 + 64. - Amiram Eldar, Jun 11 2026

Example

0.95671220568585560204582032423786663531053807143284153017564876334440171753....

Mathematica

First[RealDigits[Sqrt[2/5]*(3 + Sqrt[5])^(1/4), 10, 100]]

Prog

(PARI) (1/50) * 2^(19/20) * 5^(3/4) * gamma(9/10) * gamma(7/10) * (5+5^(1/2)) / gamma(4/5)^2
(PARI) polrootsreal(625*x^8 - 600*x^4 + 64)[4] \\ Charles R Greathouse IV, May 19 2026

Crossrefs

Cf. A147702.

Sequence in context: A388792 A292824 A388932 * A388477 A388624 A388891

Adjacent sequences: A388668 A388669 A388670 * A388672 A388673 A388674

Keyword

nonn,cons

Author

Simon Plouffe, Sep 18 2025

Status

approved