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.

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A244400 Number of unlabeled rooted trees with n nodes and maximal outdegree (branching factor) 4.

Original entry on oeis.org

1, 2, 6, 17, 49, 136, 386, 1081, 3044, 8549, 24052, 67642, 190426, 536205, 1510920, 4259418, 12014682, 33907056, 95740913, 270468869, 764450150, 2161638413, 6115252839, 17307553766, 49005101669, 138811296158, 393351362321, 1115072623713, 3162183392471
Offset: 5

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Author

Joerg Arndt and Alois P. Heinz, Jun 27 2014

Keywords

Crossrefs

Column k=4 of A244372.

Programs

  • Maple
    b:= proc(n, i, t, k) option remember; `if`(n=0, 1,
          `if`(i<1, 0, add(binomial(b((i-1)$2, k$2)+j-1, j)*
           b(n-i*j, i-1, t-j, k), j=0..min(t, n/i))))
        end:
    a:= n-> b(n-1$2, 4$2) -`if`(k=0, 0, b(n-1$2, 3$2)):
    seq(a(n), n=5..40);
  • Mathematica
    b[n_, i_, t_, k_] := b[n, i, t, k] = If[n == 0, 1, If[i < 1, 0, Sum[Binomial[b[i - 1, i - 1, k, k] + j - 1, j]* b[n - i*j, i - 1, t - j, k], {j, 0, Min[t, n/i]}]] // FullSimplify]; a[n_] := b[n-1, n-1, 4, 4] - If[n == 0, 0, b[n-1, n-1, 3, 3]]; Table[a[n], {n, 5, 40}] (* Jean-François Alcover, Feb 09 2015, after Maple *)

Formula

a(n) = A036718(n) - A000598(n).

A244401 Number of unlabeled rooted trees with n nodes and maximal outdegree (branching factor) 5.

Original entry on oeis.org

1, 2, 6, 17, 50, 142, 409, 1169, 3356, 9617, 27601, 79210, 227527, 653793, 1879867, 5407806, 15564968, 44820889, 129127761, 372177974, 1073169150, 3095721985, 8933568154, 25789862435, 74477871565, 215155604291, 621754458752, 1797297119000, 5196966140656
Offset: 6

Views

Author

Joerg Arndt and Alois P. Heinz, Jun 27 2014

Keywords

Crossrefs

Column k=5 of A244372.

Programs

  • Maple
    b:= proc(n, i, t, k) option remember; `if`(n=0, 1,
          `if`(i<1, 0, add(binomial(b((i-1)$2, k$2)+j-1, j)*
           b(n-i*j, i-1, t-j, k), j=0..min(t, n/i))))
        end:
    a:= n-> b(n-1$2, 5$2) -`if`(k=0, 0, b(n-1$2, 4$2)):
    seq(a(n), n=6..40);
  • Mathematica
    b[n_, i_, t_, k_] := b[n, i, t, k] = If[n == 0, 1, If[i < 1, 0, Sum[Binomial[b[i - 1, i - 1, k, k] + j - 1, j]* b[n - i*j, i - 1, t - j, k], {j, 0, Min[t, n/i]}]] // FullSimplify] ; a[n_] := b[n-1, n-1, 5, 5] - If[n == 0, 0, b[n-1, n-1, 4, 4]]; Table[a[n], {n, 6, 40}] (* Jean-François Alcover, Feb 09 2015, after Maple *)

Formula

a(n) = A036721(n) - A036718(n).
Previous Showing 11-12 of 12 results.