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.

A188575 Number of non-complete compositions of n.

Original entry on oeis.org

0, 1, 1, 4, 8, 14, 31, 63, 129, 248, 509, 1011, 2044, 4089, 8167, 16360, 32725, 65482, 131017, 262176, 524167, 1048678, 2096985, 4194358, 8387802, 16776408, 33550943, 67101615, 134199983, 268399122, 536793004, 1073590077, 2147187353, 4294419287, 8588940438
Offset: 1

Views

Author

N. J. A. Sloane, Apr 04 2011

Keywords

Crossrefs

Programs

  • Maple
    b:= proc(n, i, t) option remember; `if`(n=0, `if`(i=0, t!, 0),
          `if`(i<1 or n 2^(n-1) -add(b(n, i, 0), i=1..n):
    seq(a(n), n=1..40);  # Alois P. Heinz, Dec 06 2014
  • Mathematica
    b[n_, i_, t_] := b[n, i, t] = If[n == 0, If[i == 0, t!, 0], If[i<1 || nJean-François Alcover, Mar 09 2015, after Alois P. Heinz *)

Formula

a(n) = 2^(n-1) - A107429(n) ~ 2^(n-2). - Alois P. Heinz, Dec 06 2014

Extensions

More terms from Alois P. Heinz, Dec 06 2014

A188576 Number of compositions of n with the LMV property.

Original entry on oeis.org

0, 1, 1, 4, 6, 14, 26, 54, 105, 213, 423, 849, 1697, 3399, 6799, 13608, 27220, 54451, 108901, 217789, 435517, 870892, 1741467, 3482322, 6963512, 13925078, 27846979, 55689150, 111371677, 222735709, 445466058, 890938357, 1781916885, 3563957177, 7128223846
Offset: 1

Views

Author

N. J. A. Sloane, Apr 04 2011

Keywords

Comments

A composition has the largest missing value (LMV) property if its largest part is at least 2 and it does not contain a part one less than its largest part. - Andrew Howroyd, May 18 2020

Examples

			The a(5) = 6 compositions of 5 with the LMV property are: 5, 14, 41, 113, 131, 311. - _Andrew Howroyd_, May 18 2020
		

Crossrefs

Programs

  • PARI
    seq(n)={Vec(sum(k=2, n, 1/(1 - x*(1-x^(k-2))/(1-x) - x^k) - 1/(1 - x*(1-x^(k-2))/(1-x))  + O(x*x^n)), -n)} \\ Andrew Howroyd, May 18 2020

Formula

G.f.: Sum_{k>=2} 1/(1 - x*(1-x^(k-2))/(1-x) - x^k) - 1/(1 - x*(1-x^(k-2))/(1-x)). - Andrew Howroyd, May 18 2020

Extensions

Terms a(21) and beyond from Andrew Howroyd, May 18 2020
Showing 1-2 of 2 results.