A020855 Decimal expansion of 1/sqrt(98).

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

Offset

0,6

Links

Ivan Panchenko, Table of n, a(n) for n = 0..1000

Konrad Knopp, Theory and application of infinite series, Blackie & Son Limited, London and Glasgow, 1954. See p. 231.

Index entries for algebraic numbers, degree 2.

Formula

Equals sqrt(2)/14 = (1/10)*Sum_{k>=0} (1/50^n)*Product_{i=1..k} (2*i - 1)/(2*i) [Knopp]. - Stefano Spezia, Jan 30 2026

Example

0.1010152544552210749144063374435498627549765625...

Mathematica

RealDigits[1/Sqrt[98], 10, 120][[1]] (* Harvey P. Dale, Apr 07 2023 *)
realDigitsRecip[Sqrt[98]] (* The realDigitsRecip program is at A021200 *) (* Harvey P. Dale, Sep 01 2024 *)

Prog

(PARI) 1/sqrt(98) \\ Charles R Greathouse IV, May 19 2026

Crossrefs

Sequence in context: A153107 A247488 A199957 * A007292 A191583 A116558

Adjacent sequences: A020852 A020853 A020854 * A020856 A020857 A020858

Keyword

nonn,cons

Author

N. J. A. Sloane

Status

approved