A241694 Number of Carlitz compositions of n with exactly four descents.

5, 22, 72, 204, 510, 1168, 2516, 5140, 10054, 18976, 34707, 61776, 107374, 182697, 304982, 500455, 808462, 1287499, 2023697, 3142604, 4825797, 7333862, 11037829, 16462497, 24345385, 35716339, 52005295, 75186849, 107973181, 154071381, 218524581, 308162131

Offset

12,1

Comments

No two adjacent parts of a Carlitz composition are equal.

Links

Alois P. Heinz, Table of n, a(n) for n = 12..1000

Maple

b:= proc(n, i) option remember; `if`(n=0, 1,
       convert(series(add(`if`(i=j, 0, b(n-j, j)*
      `if`(j<i, x, 1)), j=1..n), x, 5), polynom))
    end:
a:= n-> coeff(b(n, 0), x, 4):
seq(a(n), n=12..50);

Crossrefs

Column k=4 of A241701.

Sequence in context: A246211 A000345 A011846 * A220733 A338707 A058750

Adjacent sequences: A241691 A241692 A241693 * A241695 A241696 A241697

Keyword

nonn

Author

Alois P. Heinz, Apr 27 2014

Status

approved