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.

A179245 Numbers that have 5 terms in their Zeckendorf representation.

Original entry on oeis.org

88, 122, 135, 140, 142, 143, 177, 190, 195, 197, 198, 211, 216, 218, 219, 224, 226, 227, 229, 230, 231, 266, 279, 284, 286, 287, 300, 305, 307, 308, 313, 315, 316, 318, 319, 320, 334, 339, 341, 342, 347, 349, 350, 352, 353, 354, 360, 362, 363, 365, 366, 367
Offset: 1

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Author

Emeric Deutsch, Jul 05 2010

Keywords

Comments

A007895(a(n)) = 5. - Reinhard Zumkeller, Mar 10 2013
Numbers that are the sum of five non-consecutive Fibonacci numbers. Their Zeckendorf representation thus consists of five 1's with at least one 0 between each pair of 1's; for example, 122 is represented as 1001010101. - Alonso del Arte, Nov 17 2013

Examples

			88  = 55 + 21 + 8 + 3 + 1.
122 = 89 + 21 + 8 + 3 + 1.
135 = 89 + 34 + 8 + 3 + 1.
140 = 89 + 34 + 13 + 3 + 1.
142 = 89 + 34 + 13 + 5 + 1.
81 is not in the sequence because, although it is the sum of five Fibonacci numbers (81 = 5 + 8 + 13 + 21 + 34), its Zeckendorf representation only has three terms: 81 = 55 + 21 + 5.
		

Crossrefs

Cf. A035517, A007895. Numbers that have m terms in their Zeckendorf representations: A179242 (m = 2), A179243 (m = 3), A179244 (m = 4), A179246 (m = 6), A179247 (m = 7), A179248 (m = 8), A179249 (m = 9), A179250 (m = 10), A179251 (m = 11), A179252 (m = 12), A179253 (m = 13).

Programs

  • Haskell
    a179245 n = a179245_list !! (n-1)
    a179245_list = filter ((== 5) . a007895) [1..]
    -- Reinhard Zumkeller, Mar 10 2013
    
  • Maple
    with(combinat): B := proc (n) local A, ct, m, j: A := proc (n) local i: for i while fibonacci(i) <= n do n-fibonacci(i) end do end proc: ct := 0: m := n: for j while 0 < A(m) do ct := ct+1: m := A(m) end do: ct+1 end proc: Q := {}: for i from fibonacci(11)-1 to 400 do if B(i) = 5 then Q := `union`(Q, {i}) else end if end do: Q;
  • Mathematica
    zeck = DigitCount[Select[Range[3000], BitAnd[#, 2*#] == 0 &], 2, 1];
    Position[zeck, 5] // Flatten (* Jean-François Alcover, Jan 30 2018 *)
  • PARI
    A048680(n)=my(k=1,s);while(n,if(n%2,s+=fibonacci(k++)); k++; n>>=1); s
    [A048680(n)|n<-[1..100],hammingweight(n)==5] \\ Charles R Greathouse IV, Nov 17 2013

Formula

a(n) = A048680(A014313(n)). - Charles R Greathouse IV, Nov 17 2013