A298750 Decimal expansion of (1/2)(1 + sqrt(5 + 4*sqrt(5))).

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

Offset

1,1

Comments

The positive zero of x^2 - x - 1- sqrt(5).

Links

Clark Kimberling, Table of n, a(n) for n = 1..10000

Index entries for algebraic numbers, degree 4.

Formula

Minimal polynomial: x^4 - 2*x^3 - x^2 + 2*x - 4. - Amiram Eldar, Jun 06 2026

Example

2.3671014909478781990...

Mathematica

r = (1/2)*(1 + Sqrt[5 + 4 Sqrt[5]]);
RealDigits[N[r, 100], 10][[1]]

Prog

(PARI) 1/2*(1+sqrt(5+4*sqrt(5))) \\ Charles R Greathouse IV, May 18 2026

Crossrefs

Cf. A298749, A298751, A298752.

Sequence in context: A068587 A218954 A182560 * A001058 A114462 A308511

Adjacent sequences: A298747 A298748 A298749 * A298751 A298752 A298753

Keyword

nonn,easy,cons

Author

Clark Kimberling, Feb 13 2018

Status

approved