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A244716

Number of compositions of n with exactly 4 transitions between different parts.

1, 6, 31, 99, 278, 654, 1390, 2714, 4927, 8531, 13963, 22134, 33767, 50283, 72470, 102891, 142375, 194202, 260093, 343973, 447906, 577636, 735540, 928009, 1159312, 1436145, 1765079, 2152787, 2608321, 3137866, 3755214, 4464420, 5284570, 6216275, 7287298, 8494233

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OFFSET

7,2

LINKS

Alois P. Heinz, Table of n, a(n) for n = 7..900

MAPLE

b:= proc(n, v) option remember; `if`(n=0, [1, 0$4],

add(`if`(v in [0, i], b(n-i, `if`(i<=n-i, i, -1)),

[0, b(n-i, `if`(i<=n-i, i, -1))[1..4][]]), i=1..n))

end:

a:= n-> b(n, 0)[5]:

seq(a(n), n=7..60);