A021509 Decimal expansion of 1/505.

0, 0, 1, 9, 8, 0, 1, 9, 8, 0, 1, 9, 8, 0, 1, 9, 8, 0, 1, 9, 8, 0, 1, 9, 8, 0, 1, 9, 8, 0, 1, 9, 8, 0, 1, 9, 8, 0, 1, 9, 8, 0, 1, 9, 8, 0, 1, 9, 8, 0, 1, 9, 8, 0, 1, 9, 8, 0, 1, 9, 8, 0, 1, 9, 8, 0, 1, 9, 8, 0, 1, 9, 8, 0, 1, 9, 8, 0, 1, 9, 8, 0, 1, 9, 8, 0, 1, 9, 8, 0, 1, 9, 8, 0, 1, 9, 8, 0, 1

Offset

0,4

Links

Table of n, a(n) for n=0..98.

Index entries for linear recurrences with constant coefficients, signature (1,-1,1).

Formula

From Chai Wah Wu, Aug 10 2020: (Start)

a(n) = a(n-1) - a(n-2) + a(n-3) for n > 3.

G.f.: -x^2*(8*x + 1)/((x - 1)*(x^2 + 1)). (End)

Example

0.00198019801980198019801980198019801980198019801980...

Mathematica

First[RealDigits[1/505, 10, 100, -1]] (* or *)
PadRight[{0}, 100, {8, 0, 1, 9}] (* Paolo Xausa, Aug 18 2025 *)
realDigitsRecip[505] (* The realDigitsRecip program is at A021200 *) (* Harvey P. Dale, Feb 01 2026 *)

Crossrefs

Sequence in context: A071063 A393784 A343055 * A154898 A199776 A344426

Adjacent sequences: A021506 A021507 A021508 * A021510 A021511 A021512

Keyword

nonn,cons,easy

Author

N. J. A. Sloane

Status

approved