A231848 A sequence of rounded numbers meaningful for entering values over several orders of magnitude in computer-human interfaces.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000, 5500

Offset

1,2

Comments

A slider in a user interface is often hard to represent when the range of numbers is large. This sequence produces a list of numbers that make it possible to select a meaningful value at all orders of magnitude.

Links

Table of n, a(n) for n=1..57.

Formula

n <= 9: n,

n > 9: (((n+8) mod 18)/2 + 1) * 10^(floor((n+8)/18)).

Mathematica

Table[If[n <= 9, n, (Mod[n + 8, 18]/2 + 1)*10^Floor[(n + 8)/18]], {n, 50}] (* T. D. Noe, Nov 27 2013 *)

Crossrefs

Sequence in context: A117923 A117924 A239616 * A200373 A140335 A004839

Adjacent sequences: A231845 A231846 A231847 * A231849 A231850 A231851

Keyword

nonn,easy

Author

Lasse Klein, Nov 14 2013

Status

approved