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.

Showing 1-2 of 2 results.

A135709 Not the sum of three distinct nonzero Fibonacci numbers.

Original entry on oeis.org

1, 2, 3, 4, 5, 7, 33, 46, 51, 53, 54, 67, 72, 74, 75, 80, 82, 83, 85, 86, 87, 88, 101, 106, 108, 109, 114, 116, 117, 119, 120, 121, 122, 127, 129, 130, 132, 133, 134, 135, 137, 138, 139, 140, 141, 142, 143, 156, 161, 163, 164, 169, 171, 172, 174, 175, 176, 177, 182, 184, 185
Offset: 1

Views

Author

N. J. A. Sloane, Mar 05 2008

Keywords

Crossrefs

Complement of A135558.

Programs

  • Maple
    # needs isA135558 from A135558
    A135709 := proc(n)
        option remember;
        local a;
        if n = 1 then
            1;
        else
            for a from procname(n-1)+1 do
                if not isA135558(a) then
                    return a;
                end if;
            end do:
        end if;
    end proc: # R. J. Mathar, Sep 09 2015
  • Mathematica
    With[{f=15},Complement[Range[Fibonacci[f]],Total/@Subsets[Fibonacci[ Range[ 2,f]],{3}]]] (* Harvey P. Dale, Sep 08 2019 *)

A160238 Numbers n such that n^2 can be expressed as the sum of three different nonzero Fibonacci numbers.

Original entry on oeis.org

3, 4, 5, 6, 7, 8, 9, 10, 12, 16, 17, 18, 20, 23, 24, 25, 32, 33, 35, 37, 40, 47, 57, 86, 112, 123, 139, 216, 322, 843, 1161, 1476, 2207, 3864, 4999, 5778, 15127, 39603, 103682, 271443, 710647, 1244196, 1860498, 4870847, 12752043
Offset: 1

Views

Author

Carmine Suriano, May 05 2009

Keywords

Comments

There exist a proper subsequence b(i)of a(n): n=[1, 2, 8, 17, 21, 24, 25, 28,29, 30, 31, 32, 33, 34, ...] such that approximatively b(i+1)=b(i)*(1+phi) where phi is 1.618... is the golden ratio and the approximation holds as a limit when i goes to infinity. For such a subsequence b(i) we have the following formula for the corresponding term when squared b(i)*b(i)=Fib(4*i+1)+Fib(4*i-1)+Fib(3). In the previous example 4999=b(9).

Examples

			4999*4999=24990001=Fib(37)+Fib(35)+Fib(3)
		

Crossrefs

Extensions

Inserted 4 (with 4^2=13+1+2), 6 (with 36=21+2+13), 12 (with 12^2=89+21+34) etc. Added "nonzero" to definition - R. J. Mathar, Oct 23 2010
Showing 1-2 of 2 results.