A246730 Decimal expansion of r_9, the 9th smallest radius < 1 for which a compact packing of the plane exists, with disks of radius 1 and r_9.

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

Offset

0,1

Links

Table of n, a(n) for n=0..101.

Steven R. Finch, Errata and Addenda to Mathematical Constants, p. 62.

Index entries for algebraic numbers, degree 4.

Formula

First root of x^4 - 10x^2 - 8x + 9.

Example

0.637555977231945793491317167739909596737570842457401874067...

Mathematica

RealDigits[Root[x^4 - 10x^2 - 8x + 9, x, 1], 10, 102] // First

Prog

(PARI) polrootsreal(x^4-10*x^2-8*x+9)[1] \\ Charles R Greathouse IV, Feb 11 2025

Crossrefs

Cf. A246723 (r_1), A246724 (r_2), A246725 (r_3), A246726 (r_4), A246727 (r_5), A002193 (r_6 = sqrt(2)-1), A246728 (r_7), A246729 (r_8).

Sequence in context: A182549 A260660 A011191 * A200239 A097676 A251780

Adjacent sequences: A246727 A246728 A246729 * A246731 A246732 A246733

Keyword

nonn,cons,easy

Author

Jean-François Alcover, Sep 02 2014

Status

approved