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A241696
Number of Carlitz compositions of n with exactly six descents.
2
13, 81, 336, 1151, 3437, 9286, 23271, 54846, 122857, 263680, 545412, 1092394, 2126688, 4036767, 7490050, 13614573, 24287970, 42592752, 73525406, 125089010, 209962350, 348026885, 570159824, 923885796, 1481735623, 2353522164, 3704254256, 5780115565, 8945915366
OFFSET
18,1
COMMENTS
No two adjacent parts of a Carlitz composition are equal.
LINKS
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, 7), polynom))
end:
a:= n-> coeff(b(n, 0), x, 6):
seq(a(n), n=18..50);
CROSSREFS
Column k=6 of A241701.
Sequence in context: A297678 A189451 A133718 * A052255 A362545 A082203
KEYWORD
nonn
AUTHOR
_Alois P. Heinz_, Apr 27 2014
STATUS
approved