cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A167410 Disorderly Numbers: numbers not in A167408 (orderly numbers).

Original entry on oeis.org

3, 4, 6, 10, 14, 15, 16, 18, 21, 22, 24, 25, 26, 28, 30, 32, 33, 34, 35, 36, 39, 40, 42, 44, 45, 46, 48, 49, 50, 51, 54, 55, 56, 60, 62, 63, 64, 65, 66, 69, 70, 74, 75, 77, 78, 80, 81, 82, 84, 85, 86, 88, 90, 91, 92, 93, 94, 95, 96, 98, 99, 100, 102, 104, 105, 106, 108
Offset: 1

Views

Author

Andrew Weimholt, Nov 03 2009

Keywords

Examples

			3 is disorderly because there exists no K > 2=tau(3), such that {1,3} == {1,2} mod K.
		

Crossrefs

Cf. A167408 - Orderly Numbers
Cf. A167409 - Very Orderly Numbers ( K = tau(N)+1 )
Cf. A167411 - Minimal K Values for the Orderly Numbers

Programs

  • Mathematica
    orderlyQ[n_] := (For[dd = Divisors[n]; tau = Length[dd]; k = 3, k <= Max[tau + 4, Last[dd] - 2], k++, If[Union[Mod[dd, k]] == Range[tau], Return[True]]]; False); Select[Range[120], !orderlyQ[#]&] (* Jean-François Alcover, Nov 03 2016 *)