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 1-3 of 3 results.

A135302 Square array of numbers A(n,k) (n>=0, k>=0) of transitive reflexive early confluent binary relations R on n labeled elements where |{y : xRy}| <= k for all x, read by antidiagonals.

Original entry on oeis.org

1, 0, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 4, 1, 1, 0, 1, 13, 4, 1, 1, 0, 1, 62, 26, 4, 1, 1, 0, 1, 311, 168, 26, 4, 1, 1, 0, 1, 1822, 1416, 243, 26, 4, 1, 1, 0, 1, 11593, 13897, 2451, 243, 26, 4, 1, 1, 0, 1, 80964, 153126, 29922, 2992, 243, 26, 4, 1, 1, 0, 1, 608833, 1893180, 420841, 41223, 2992, 243, 26, 4, 1, 1
Offset: 0

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Author

Alois P. Heinz, Dec 04 2007

Keywords

Comments

R is early confluent iff (xRy and xRz) implies (yRz or zRy) for all x, y, z.

Examples

			Table A(n,k) begins:
  1, 1,   1,    1,    1,    1, ...
  0, 1,   1,    1,    1,    1, ...
  0, 1,   4,    4,    4,    4, ...
  0, 1,  13,   26,   26,   26, ...
  0, 1,  62,  168,  243,  243, ...
  0, 1, 311, 1416, 2451, 2992, ...
		

References

  • A. P. Heinz (1990). Analyse der Grenzen und Möglichkeiten schneller Tableauoptimierung. PhD Thesis, Albert-Ludwigs-Universität Freiburg, Freiburg i. Br., Germany.

Crossrefs

Main diagonal gives A052880.
A(n,n)-A(n,n-1) gives A000670.
Cf. A135313.

Programs

  • Maple
    t:= proc(k) option remember; `if`(k<0, 0,
           unapply(exp(add(x^m/m! *t(k-m)(x), m=1..k)), x))
        end:
    A:= proc(n, k) option remember;
          coeff(series(t(k)(x), x, n+1), x, n) *n!
        end:
    seq(seq(A(d-i, i), i=0..d), d=0..15);
  • Mathematica
    t[0, ] = 1; t[k, x_] := t[k, x] = Exp[Sum[x^m/m!*t[k-m, x], {m, 1, k}]]; a[0, 0] = 1; a[, 0] = 0; a[n, k_] := SeriesCoefficient[t[k, x], {x, 0, n}]*n!; Table[a[n-k, k], {n, 0, 11}, {k, 0, n}] // Flatten (* Jean-François Alcover, Dec 06 2013, after Maple *)

Formula

E.g.f. of column k=0: t_0(x) = 1; e.g.f. of column k>0: t_k(x) = exp (Sum_{m=1..k} x^m/m! * t_{k-m}(x)).
A(n,k) = Sum_{i=0..k} A135313(n,i).

A218098 Number of transitive reflexive early confluent binary relations R on n labeled elements with max_{x}(|{y : xRy}|) = 8.

Original entry on oeis.org

545835, 27733869, 1173919350, 47488375440, 1933688266686, 81009491387682, 3527548086703069, 160415345420268510, 7631859877504516225, 379961855272982538127, 19785139747357478264082, 1076480694153554931849504, 61126131119735946242652270
Offset: 8

Views

Author

Alois P. Heinz, Oct 20 2012

Keywords

Comments

R is early confluent iff (xRy and xRz) implies (yRz or zRy) for all x, y, z.

References

  • A. P. Heinz (1990). Analyse der Grenzen und Möglichkeiten schneller Tableauoptimierung. PhD Thesis, Albert-Ludwigs-Universität Freiburg, Freiburg i. Br., Germany.

Crossrefs

Column k=8 of A135313.

Programs

  • Maple
    t:= proc(k) option remember; `if`(k<0, 0,
          unapply(exp(add(x^m/m! *t(k-m)(x), m=1..k)), x))
        end:
    egf:= t(8)(x)-t(7)(x):
    a:= n-> n!* coeff(series(egf, x, n+1), x, n):
    seq(a(n), n=8..22);
  • Mathematica
    m = 8; t[k_] := t[k] = If[k<0, 0, Function[x, Exp[Sum[x^m/m!*t[k-m][x], {m, 1, k}]]]] ; egf = t[m][x]-t[m-1][x]; a[n_] := n!*Coefficient[Series[egf, {x, 0, n+1}], x, n]; Table[a[n], {n, m, 22}] (* Jean-François Alcover, Feb 14 2014, after Maple *)

Formula

E.g.f.: t_8(x)-t_7(x), with t_k(x) = exp (Sum_{m=1..k} x^m/m! * t_{k-m}(x)) if k>=0 and t_k(x) = 0 else.
a(n) = A210916(n) - A210915(n).

A218099 Number of transitive reflexive early confluent binary relations R on n labeled elements with max_{x}(|{y : xRy}|) = 9.

Original entry on oeis.org

7087261, 451238935, 22913136730, 1087116745385, 51075201835515, 2437976801668408, 119752042470064290, 6093096859120003590, 322215964319093498225, 17735784941946000072572, 1016521929886047797022408, 60650840653136697085038930, 3764766650086543657134295955
Offset: 9

Views

Author

Alois P. Heinz, Oct 20 2012

Keywords

Comments

R is early confluent iff (xRy and xRz) implies (yRz or zRy) for all x, y, z.

References

  • A. P. Heinz (1990). Analyse der Grenzen und Möglichkeiten schneller Tableauoptimierung. PhD Thesis, Albert-Ludwigs-Universität Freiburg, Freiburg i. Br., Germany.

Crossrefs

Column k=9 of A135313.

Programs

  • Maple
    t:= proc(k) option remember; `if`(k<0, 0,
          unapply(exp(add(x^m/m! *t(k-m)(x), m=1..k)), x))
        end:
    egf:= t(9)(x)-t(8)(x):
    a:= n-> n!* coeff(series(egf, x, n+1), x, n):
    seq(a(n), n=9..22);
  • Mathematica
    m = 9; t[k_] := t[k] = If[k<0, 0, Function[x, Exp[Sum[x^m/m!*t[k-m][x], {m, 1, k}]]]] ; egf = t[m][x]-t[m-1][x]; a[n_] := n!*Coefficient[Series[egf, {x, 0, n+1}], x, n]; Table[a[n], {n, m, 22}] (* Jean-François Alcover, Feb 14 2014, after Maple *)

Formula

E.g.f.: t_9(x)-t_8(x), with t_k(x) = exp (Sum_{m=1..k} x^m/m! * t_{k-m}(x)) if k>=0 and t_k(x) = 0 else.
a(n) = A210917(n) - A210916(n).
Showing 1-3 of 3 results.