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A241697
Number of Carlitz compositions of n with exactly seven descents.
2
21, 150, 688, 2561, 8253, 23930, 64030, 160539, 381379, 865676, 1889308, 3984311, 8151834, 16234161, 31554397, 59999259, 111824744, 204629354, 368190175, 652238928, 1138836325, 1961870558, 3337496363, 5611246209, 9330350788, 15353900381, 25019429935
OFFSET
21,1
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, 8), polynom))
end:
a:= n-> coeff(b(n, 0), x, 7):
seq(a(n), n=21..50);
CROSSREFS
Column k=7 of A241701.
Sequence in context: A253459 A041850 A239123 * A358994 A239569 A219599
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Apr 27 2014
STATUS
approved