A124759 Sum of products of consecutive terms for compositions in standard order.

0, 0, 0, 1, 0, 2, 2, 2, 0, 3, 4, 3, 3, 4, 3, 3, 0, 4, 6, 4, 6, 6, 4, 4, 4, 6, 6, 5, 4, 5, 4, 4, 0, 5, 8, 5, 9, 8, 5, 5, 8, 9, 8, 7, 5, 6, 5, 5, 5, 8, 9, 7, 8, 8, 6, 6, 5, 7, 7, 6, 5, 6, 5, 5, 0, 6, 10, 6, 12, 10, 6, 6, 12, 12, 10, 9, 6, 7, 6, 6, 10, 12, 12, 10, 10, 10, 8, 8, 6, 8, 8, 7, 6, 7, 6, 6, 6, 10

Offset

0,6

Comments

The standard order of compositions is given by A066099.

Links

Alois P. Heinz, Rows n = 0..14, flattened

Formula

For a composition b(1),...,b(k), a(n) = Sum_{i=1}^{k-1} b(i) b(i+1).

Example

Composition number 11 is 2,1,1; 2*1+1*1 = 3, so a(11) = 3.
The table starts:
0
0
0 1
0 2 2 2

Crossrefs

Cf. A066099, A070939, A011782 (row lengths), A045618 (row sums).

Sequence in context: A134577 A071442 A174740 * A071295 A296062 A214178

Adjacent sequences: A124756 A124757 A124758 * A124760 A124761 A124762

Keyword

easy,nonn,tabf

Author

Franklin T. Adams-Watters, Nov 06 2006

Status

approved