

A210726


a(2)=1, a(3)=2; thereafter a(n) = 2a(n1)a(n2)+A046919(n).


2



1, 2, 4, 9, 22, 59, 169, 506, 1577, 5078, 16729, 56098, 190981, 658442, 2294164, 8066363, 28588554, 102036631, 366458118, 1323463507, 4803734390, 17515357533, 64128879398, 235682969485, 869175349090, 3215674910037, 11932102898252, 44396448313385, 165608308422048, 619217961493403, 2320410595131693, 8713343724905902, 32782954997996347, 123567462151713252, 466559336920866937, 1764469819249171154
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OFFSET

2,2


COMMENTS

According to Riordan (1968), this is the number of possible score sequences in a tournament with n nodes, but the latter is given by A000571, which is a different sequence.


LINKS

Table of n, a(n) for n=2..37.
J. Riordan, The number of score sequences in tournaments, J. Combin. Theory, 5 (1968), 8789.


CROSSREFS

Cf. A046919.
Sequence in context: A035053 A000571 A077003 * A046917 A237770 A187044
Adjacent sequences: A210723 A210724 A210725 * A210727 A210728 A210729


KEYWORD

nonn


AUTHOR

N. J. A. Sloane, May 09 2012


STATUS

approved



