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.

A018910 Pisot sequence L(4,5).

Original entry on oeis.org

4, 5, 7, 10, 15, 23, 36, 57, 91, 146, 235, 379, 612, 989, 1599, 2586, 4183, 6767, 10948, 17713, 28659, 46370, 75027, 121395, 196420, 317813, 514231, 832042, 1346271, 2178311, 3524580, 5702889, 9227467, 14930354, 24157819, 39088171, 63245988, 102334157, 165580143
Offset: 0

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Keywords

Crossrefs

See A008776 for definitions of Pisot sequences.

Programs

  • Mathematica
    LinearRecurrence[{2, 0, -1}, {4, 5, 7}, 40] (* Jean-François Alcover, Dec 12 2016 *)
  • PARI
    pisotL(nmax, a1, a2) = {
      a=vector(nmax); a[1]=a1; a[2]=a2;
      for(n=3, nmax, a[n] = ceil(a[n-1]^2/a[n-2]));
      a
    }
    pisotL(50, 4, 5) \\ Colin Barker, Aug 07 2016

Formula

a(n) = Fib(n+3)+2 = A020743(n-2) = A157725(n+3); a(n) = 2a(n-1) - a(n-3).
G.f.: -(-4+3*x+3*x^2)/(x-1)/(x^2+x-1) = -2/(x-1)+(-x-2)/(x^2+x-1) . - R. J. Mathar, Nov 23 2007

A048584 Pisot sequence L(5,7).

Original entry on oeis.org

5, 7, 10, 15, 23, 36, 57, 91, 146, 235, 379, 612, 989, 1599, 2586, 4183, 6767, 10948, 17713, 28659, 46370, 75027, 121395, 196420, 317813, 514231, 832042, 1346271, 2178311, 3524580, 5702889, 9227467, 14930354, 24157819, 39088171, 63245988, 102334157, 165580143
Offset: 0

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Author

Keywords

Comments

a(n)= BA^(n)B(1), n>=0, with compositions of Wythoff's complementary A(n):=A000201(n) and B(n)=A001950(n) sequences. See the W. Lang link under A135817 for the Wythoff representation of numbers (with A as 1 and B as 0 and the argument 1 omitted). E.g. 5=`00`, 7=`010`, 10=`0110`, 15=`01110`,..., in Wythoff code.

Crossrefs

Subsequence of A018910. See A008776 for definitions of Pisot sequences.

Programs

  • Mathematica
    LinearRecurrence[{2,0,-1},{5,7,10},40] (* Harvey P. Dale, Oct 02 2016 *)
  • PARI
    pisotL(nmax, a1, a2) = {
      a=vector(nmax); a[1]=a1; a[2]=a2;
      for(n=3, nmax, a[n] = ceil(a[n-1]^2/a[n-2]));
      a
    }
    pisotL(50, 5, 7) \\ Colin Barker, Aug 07 2016

Formula

a(n) = Fib(n+4)+2. a(n) = 2a(n-1) - a(n-3).
a(n)=A020743(n-1), n>0. - R. J. Mathar, Oct 15 2008
Showing 1-2 of 2 results.