login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A167410
Disorderly Numbers: numbers not in A167408 (orderly numbers).
4
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
1,1
EXAMPLE
3 is disorderly because there exists no K > 2=tau(3), such that {1,3} == {1,2} mod K.
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 *)
CROSSREFS
Cf. A167408 - Orderly Numbers
Cf. A167409 - Very Orderly Numbers ( K = tau(N)+1 )
Cf. A167411 - Minimal K Values for the Orderly Numbers
Sequence in context: A365614 A074321 A253049 * A302340 A310003 A085378
KEYWORD
nonn
AUTHOR
Andrew Weimholt, Nov 03 2009
STATUS
approved