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A241693 Number of Carlitz compositions of n with exactly three descents. 2
3, 11, 31, 78, 175, 363, 715, 1342, 2421, 4237, 7208, 11971, 19473, 31083, 48787, 75437, 115046, 173263, 257972, 380039, 554400, 801452, 1148805, 1633699, 2306108, 3232635, 4501745, 6230400, 8572442, 11729536, 15965001, 21621202, 29141879, 39100192, 52233835 (list; graph; refs; listen; history; text; internal format)
OFFSET

9,1

COMMENTS

No two adjacent parts of a Carlitz composition are equal.

LINKS

Alois P. Heinz, Table of n, a(n) for n = 9..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, 4), polynom))

    end:

a:= n-> coeff(b(n, 0), x, 3):

seq(a(n), n=9..50);

CROSSREFS

Column k=3 of A241701.

Sequence in context: A245931 A190590 A341705 * A087323 A236752 A034543

Adjacent sequences:  A241690 A241691 A241692 * A241694 A241695 A241696

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Apr 27 2014

STATUS

approved

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Last modified August 1 09:36 EDT 2021. Contains 346385 sequences. (Running on oeis4.)