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.

A167411 a(n) = the minimal K value for the orderly number A167408(n).

Original entry on oeis.org

2, 3, 3, 5, 5, 7, 3, 7, 11, 3, 17, 7, 3, 5, 3, 29, 5, 5, 3, 41, 3, 7, 3, 5, 5, 3, 59, 5, 7, 3, 13, 71, 7, 7, 3, 5, 3, 5, 3, 101, 3, 107, 3, 7, 5, 7, 5, 3, 5, 3, 137, 3, 149, 5, 5, 11, 7, 7, 3, 3, 5, 5, 3, 179, 7, 3, 191, 3, 197, 5, 11, 5, 13, 3, 227, 3, 7, 5, 3, 239, 7, 7, 5, 3, 11, 3, 3, 5, 3
Offset: 1

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Author

Andrew Weimholt, Nov 03 2009

Keywords

Examples

			a(6) = 7, because A167408(6) = 9, and divisors of 9 = {1,9,3} == {1,2,3} mod 7.
		

Crossrefs

Cf. A167408 - Orderly Numbers.
Cf. A167409 - Very Orderly Numbers ( K = tau(N)+1 ).
Cf. A167410 - Disorderly Numbers - numbers not in A167408.

Programs

  • Mathematica
    orderlyQkValue[n_] := (For[dd = Divisors[n]; tau = Length[dd]; k = 2, k <= Max[tau + 4, Last[dd] - 2], k++, If[Union[Mod[dd, k]] == Range[tau], Return[{True, k}]]]; {False, 0}); A167411List = Select[{#, orderlyQkValue[#]}& /@ Range[400] , #[[2, 1]]&][[All, 2, 2]] (* Jean-François Alcover, Nov 03 2016 *)