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A124759
Sum of products of consecutive terms for compositions in standard order.
1
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
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
KEYWORD
easy,nonn,tabf
AUTHOR
STATUS
approved