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.

A328208 Zeckendorf-Niven numbers: numbers divisible by the number of terms in their Zeckendorf representation (A007895).

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 8, 10, 12, 13, 14, 16, 18, 21, 22, 24, 26, 27, 30, 34, 36, 42, 45, 48, 55, 56, 58, 60, 66, 68, 69, 72, 76, 78, 80, 81, 84, 89, 90, 92, 93, 94, 96, 99, 102, 105, 108, 110, 111, 116, 120, 126, 132, 135, 140, 144, 146, 150, 152, 153, 156, 159, 162
Offset: 1

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Author

Amiram Eldar, Oct 07 2019

Keywords

Examples

			12 is in the sequence since A007895(12) = 3 and 3 is a divisor of 12.
		

References

  • Andrew Ray, On the natural density of the k-Zeckendorf Niven numbers, Ph.D. dissertation, Central Missouri State University, 2005.

Crossrefs

Programs

  • Maple
    fib:= combinat:-fibonacci:
    phi:= 1/2 + sqrt(5)/2:
    fibapp:= n -> phi^n/sqrt(5):
    invfib := proc(x::posint)
      local q, n;
      q:= evalf((ln(x+1/2) + ln(5)/2)/ln(phi));
      n:= floor(q);
      if fib(n) <= x then
        while fib(n+1) <= x do
          n := n+1
        end do
      else
        while fib(n) > x do
          n := n-1
        end do
      end if;
      n
    end proc:
    zeck:= proc(x) local n;
     if x = 0 then 0
     else
       n:= invfib(x);
       F[n] + zeck(x-fib(n));
     fi
    end proc:
    filter:= n -> n mod nops(zeck(n)) = 0:
    select(filter, [$1..200]); # Robert Israel, Oct 25 2019
  • Mathematica
    z[n_] := Length[DeleteCases[NestWhileList[# - Fibonacci[Floor[Log[Sqrt[5]*# + 3/2]/Log[GoldenRatio]]] &, n, # > 1 &], 0]]; aQ[n_] := Divisible[n, z[n]]; Select[Range[1000], aQ] (* after Alonso del Arte at A007895 *)