A108693 - OEIS

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A108693

Number of circular sequences of distinct positive integers between 1 and n such that the sum of any two consecutive elements is at least n+1.

0

1, 2, 4, 8, 15, 36, 80, 244, 677, 2530

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OFFSET

1,2

LINKS

Table of n, a(n) for n=1..10.

EXAMPLE

For n=4 the circular sequences are 3, 4, 14, 23, 24, 34, 234 and 243, so a(4)=8.

CROSSREFS

Sequence in context: A145671 A316522 A317712 * A371351 A026096 A098864

Adjacent sequences: A108690 A108691 A108692 * A108694 A108695 A108696

KEYWORD

nonn

AUTHOR

Daniel Gulotta (dgulotta(AT)mit.edu), Jun 18 2005

STATUS

approved