A176435 Decimal expansion of (21+5*sqrt(21))/6.

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

Offset

1,1

Comments

Continued fraction expansion of (21+5*sqrt(21))/6 is A010705 preceded by 7.

Links

Daniel Starodubtsev, Table of n, a(n) for n = 1..10000

Index entries for algebraic numbers, degree 2.

Formula

Minimal polynomial: 3*x^2 - 21*x - 7. - Amiram Eldar, Apr 27 2026

Example

7.31881307912986667215670599477334040748704714730664...

Mathematica

RealDigits[(21+5*Sqrt[21])/6, 10, 120][[1]] (* Harvey P. Dale, Feb 20 2022 *)

Crossrefs

Cf. A010477 (decimal expansion of sqrt(21)), A010705 (repeat 3, 7).

Sequence in context: A125681 A021899 A397198 * A389745 A393640 A133722

Adjacent sequences: A176432 A176433 A176434 * A176436 A176437 A176438

Keyword

cons,nonn

Author

Klaus Brockhaus, Apr 19 2010

Status

approved