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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A340415 Number of sets of nonempty words with a total of n letters over octonary alphabet such that within each word every letter of the alphabet is at least as frequent as the subsequent alphabet letter.

Original entry on oeis.org

1, 1, 3, 13, 60, 326, 2065, 14508, 116845, 676579, 4533285, 29337447, 204274255, 1401597565, 10464806200, 75242714351, 588938921227, 4060713617519, 30141138974325, 217182619165093, 1630762746458645, 11987353708674543, 91946531392941646, 683807822490949653
Offset: 0

Views

Author

Alois P. Heinz, Jan 06 2021

Keywords

Crossrefs

Column k=8 of A292795.
Cf. A226878.

Programs

  • Maple
    b:= proc(n, i, t) option remember; `if`(t=1, 1/n!,
          add(b(n-j, j, t-1)/j!, j=i..n/t))
        end:
    g:= (n, k)-> `if`(k=0, `if`(n=0, 1, 0), n!*b(n, 0, k)):
    h:= proc(n, i, k) option remember; `if`(n=0, 1, `if`(i<1, 0,
          add(h(n-i*j, i-1, k)*binomial(g(i, k), j), j=0..n/i)))
        end:
    a:= n-> h(n$2, min(n, 8)):
    seq(a(n), n=0..32);

Formula

G.f.: Product_{j>=1} (1+x^j)^A226878(j).

A340416 Number of sets of nonempty words with a total of n letters over nonary alphabet such that within each word every letter of the alphabet is at least as frequent as the subsequent alphabet letter.

Original entry on oeis.org

1, 1, 3, 13, 60, 326, 2065, 14508, 116845, 1039459, 6710565, 48872487, 350817295, 2619846205, 20019859960, 158415989711, 1300359929707, 10644485545679, 91963547963925, 715052566412773, 5842504427274965, 47435773495721103, 390005026265914606, 3225674439739003413
Offset: 0

Views

Author

Alois P. Heinz, Jan 07 2021

Keywords

Crossrefs

Column k=9 of A292795.
Cf. A226879.

Programs

  • Maple
    b:= proc(n, i, t) option remember; `if`(t=1, 1/n!,
          add(b(n-j, j, t-1)/j!, j=i..n/t))
        end:
    g:= (n, k)-> `if`(k=0, `if`(n=0, 1, 0), n!*b(n, 0, k)):
    h:= proc(n, i, k) option remember; `if`(n=0, 1, `if`(i<1, 0,
          add(h(n-i*j, i-1, k)*binomial(g(i, k), j), j=0..n/i)))
        end:
    a:= n-> h(n$2, min(n, 9)):
    seq(a(n), n=0..32);

Formula

G.f.: Product_{j>=1} (1+x^j)^A226879(j).

A340417 Number of sets of nonempty words with a total of n letters over denary alphabet such that within each word every letter of the alphabet is at least as frequent as the subsequent alphabet letter.

Original entry on oeis.org

1, 1, 3, 13, 60, 326, 2065, 14508, 116845, 1039459, 10339365, 72459687, 581246095, 4483235005, 36697945720, 298344453071, 2601248199787, 22469318990159, 208007606797845, 1867498245975013, 17978675539264085, 153181998023380623, 1392447676785436846
Offset: 0

Views

Author

Alois P. Heinz, Jan 07 2021

Keywords

Crossrefs

Column k=10 of A292795.
Cf. A226880.

Programs

  • Maple
    b:= proc(n, i, t) option remember; `if`(t=1, 1/n!,
          add(b(n-j, j, t-1)/j!, j=i..n/t))
        end:
    g:= (n, k)-> `if`(k=0, `if`(n=0, 1, 0), n!*b(n, 0, k)):
    h:= proc(n, i, k) option remember; `if`(n=0, 1, `if`(i<1, 0,
          add(h(n-i*j, i-1, k)*binomial(g(i, k), j), j=0..n/i)))
        end:
    a:= n-> h(n$2, min(n, 10)):
    seq(a(n), n=0..32);

Formula

G.f.: Product_{j>=1} (1+x^j)^A226880(j).
Previous Showing 11-13 of 13 results.