A096571 Number of compositions of n with first part 3 and no equal adjacent parts; this is column 3 of the array in A096568.

0, 0, 1, 1, 1, 2, 3, 6, 12, 20, 33, 59, 104, 181, 319, 557, 971, 1705, 2985, 5218, 9138, 15993, 27984, 48992, 85749, 150061, 262656, 459721, 804597, 1408263, 2464815, 4313962, 7550509, 13215258, 23129801, 40482775, 70854694, 124012664

Offset

1,6

Links

Table of n, a(n) for n=1..38.

Formula

Define s(0)=1, T(1, 1)=1 and T(i, j)=0 for j>i. For n>=2 and 1<=k<=n, define s(n)=T(n, 1)+T(n, 2)+...+T(n, n) and T(n, k)=s(n-k)-T(n-k, k). (This is array A096568.)

Crossrefs

Cf. A003242, A096568, A096569, A096570, A096572.

Sequence in context: A233422 A361382 A079708 * A227940 A081156 A326172

Adjacent sequences: A096568 A096569 A096570 * A096572 A096573 A096574

Keyword

nonn

Author

Clark Kimberling, Jun 27 2004

Status

approved