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.

A336007 Numbers whose mixed Zeckendorf-Lucas representation is not a Zeckendorf or Lucas representation. See Comments.

Original entry on oeis.org

17, 25, 28, 38, 41, 45, 46, 52, 53, 59, 62, 66, 67, 72, 73, 74, 75, 81, 82, 84, 85, 86, 93, 96, 100, 101, 106, 107, 108, 109, 114, 117, 118, 119, 120, 121, 122, 128, 129, 131, 132, 133, 136, 137, 138, 139, 140, 148, 151, 155, 156, 161, 162, 163, 164, 169
Offset: 1

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Author

Clark Kimberling, Jul 06 2020

Keywords

Comments

Suppose that B1 and B2 are increasing sequences of positive integers, and let B be the increasing sequence of numbers in the union of B1 and B2. Every positive integer n has a unique representation given by the greedy algorithm with B1 as base, and likewise for B2 and B.

Examples

			17 = 13 + 4;
25 = 21 + 4;
28 = 21 + 7.
		

Crossrefs

Programs

  • Mathematica
    fibonacciQ[n_] := IntegerQ[Sqrt[5 n^2 + 4]] || IntegerQ[Sqrt[5 n^2 - 4]];
    Attributes[fibonacciQ] = {Listable};
    lucasQ[n_] := IntegerQ[Sqrt[5 n^2 + 20]] || IntegerQ[Sqrt[5 n^2 - 20]];
    Attributes[lucasQ] = {Listable};
    s = Reverse[Union[Flatten[Table[{Fibonacci[n + 1], LucasL[n - 1]}, {n, 1, 22}]]]];
    u = Map[#[[1]] &, Select[Map[{#[[1]], {Apply[And, fibonacciQ[#[[2]]]],
           Apply[And, lucasQ[#[[2]]]]}} &, Map[{#, DeleteCases[
            s Reap[FoldList[(Sow[Quotient[#1, #2]]; Mod[#1, #2]) &, #,
                s]][[2, 1]], 0]} &,
         Range[500]]], #[[2]] == {False, False} &]]
    (* Peter J. C. Moses, Jun 14 2020 *)