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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A241803 Number of ballot sequences of length n having exactly ten descents.

Original entry on oeis.org

1, 279, 19125, 651245, 14366695, 233582056, 3019039806, 32552281146, 302772441833, 2489676658658, 18436266612425, 124754494349824, 780244984225568, 4553372454106529, 24982642521157848, 129722480362398371, 640852528623371007, 3026558205823169395
Offset: 15

Views

Author

Joerg Arndt and Alois P. Heinz, Apr 28 2014

Keywords

Examples

			a(15) = 1: [1,2,1,3,2,1,4,3,2,1,5,4,3,2,1].

Crossrefs

Column k=10 of A238121 and of A238122.

A241804 Number of ballot sequences of length 2n having exactly n descents.

Original entry on oeis.org

1, 0, 0, 1, 9, 112, 1582, 26159, 486170, 10131071, 233582056, 5895589738, 161776346286, 4794754890798, 152576687930997, 5187562649814737, 187666786444911220, 7196725552061993554, 291572346138097726746, 12443163766976461627878, 557880276243757014820691
Offset: 0

Views

Author

Joerg Arndt and Alois P. Heinz, Apr 28 2014

Keywords

Examples

			a(3) = 1: [1,2,1,3,2,1].
a(4) = 9: [1,2,1,2,1,3,2,1], [1,2,1,3,1,4,2,1], [1,2,1,3,2,1,2,1], [1,2,1,3,2,1,3,1], [1,2,1,3,2,1,3,2], [1,2,1,3,2,1,4,1], [1,2,1,3,2,1,4,2], [1,2,1,3,2,1,4,3], [1,2,1,3,2,4,3,1].

Formula

a(n) = A238121(2n,n) = A238122(2n,n).

A241805 Number of ballot sequences of length 2n+1 having exactly n descents.

Original entry on oeis.org

1, 1, 3, 17, 146, 1615, 21895, 349021, 6385041, 131722015, 3019039806, 76052414727, 2087753039823, 61995921313948, 1979138443335708, 67572818967182165, 2456489615222703765, 94710044795486692712, 3859301582400404494533, 165700769713109075755060
Offset: 0

Views

Author

Joerg Arndt and Alois P. Heinz, Apr 28 2014

Keywords

Examples

			a(1) = 1: [1,2,1].
a(2) = 3: [1,2,1,2,1], [1,2,1,3,1], [1,2,1,3,2].

Formula

a(n) = A238121(2n+1,n) = A238122(2n+1,n).
Previous Showing 11-13 of 13 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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