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A244716 Number of compositions of n with exactly 4 transitions between different parts. 2
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 (list; graph; refs; listen; history; text; internal format)
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);

MATHEMATICA

b[n_, v_] := b[n, v] = If[n == 0, 1, Expand[Sum[b[n - i, i]*

     If[v == 0 || v == i, 1, x], {i, n}]]];

a[n_] := Coefficient[b[n, 0], x, 4];

Table[a[n], {n, 7, 60}] (* Jean-Fran├žois Alcover, Aug 29 2021, after A238279 Maple code *)

CROSSREFS

Column k=4 of A238279.

Sequence in context: A273790 A096959 A112562 * A024447 A303172 A143568

Adjacent sequences:  A244713 A244714 A244715 * A244717 A244718 A244719

KEYWORD

nonn

AUTHOR

Joerg Arndt and Alois P. Heinz, Jul 04 2014

STATUS

approved

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Last modified May 29 02:45 EDT 2022. Contains 354122 sequences. (Running on oeis4.)