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A000570 Number of tournaments on n nodes determined by their score vectors. +0
4
1, 1, 2, 4, 7, 11, 18, 31, 53, 89, 149, 251, 424, 715, 1204, 2028, 3418, 5761, 9708, 16358, 27565, 46452, 78279, 131910, 222285, 374581, 631222, 1063696, 1792472, 3020560, 5090059, 8577449, 14454177, 24357268, 41045336, 69167021, 116555915 (list; graph; listen)
OFFSET

1,3

REFERENCES

Prasad Tetali, A characterization of unique tournaments, J. Comb Theory B 72 (1) (1998), 157-159.

LINKS

T. D. Noe, Table of n, a(n) for n=1..500

Index entries for sequences related to tournaments

FORMULA

a(n) = a(n-5) + a(n-4) + a(n-3) + a(n-1). - Jon Schoenfield (jonscho(AT)hiwaay.net), Aug 07 2006

MAPLE

A000570 := proc(n) option remember; if n <= 2 then RETURN(1) elif n=3 then RETURN(2) elif n=4 then RETURN(4) elif n=5 then RETURN(7) else A000570(n-1)+A000570(n-3)+A000570(n-4)+A000570(n-5); fi; end;

CROSSREFS

Sequence in context: A091838 A004696 A018063 this_sequence A023426 A157134 A127926

Adjacent sequences: A000567 A000568 A000569 this_sequence A000571 A000572 A000573

KEYWORD

nonn,nice

AUTHOR

Prasad Tetali [ tetali(AT)math.gatech.edu ]

EXTENSIONS

More terms from James A. Sellers (sellersj(AT)math.psu.edu), Feb 06 2000

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Last modified March 19 13:18 EDT 2010. Contains 173632 sequences.


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