

A140961


Number of 3 X n {0,1}matrices such that: (a) first and second row have a common 1, (b) second and third row have a common 1.


0



1, 17, 205, 2129, 20341, 184457, 1615405, 13808609, 116015461, 962575097, 7913168605, 64610052689, 524855128981, 4247421698537, 34274519697805, 275985344786369, 2218709434248901, 17815093293410777, 142915542082163005, 1145704555158361649, 9179974972732223221
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OFFSET

1,2


LINKS

Table of n, a(n) for n=1..21.
Andy Fugard, Counting firstorder models (with n individuals) of syllogisms.
Index entries for linear recurrences with constant coefficients, signature (19,118,240).


FORMULA

a(n) = 8^n2*6^n+5^n.
G.f.: x*(2*x1)/((5*x1)*(6*x1)*(8*x1)). [Colin Barker, Nov 05 2012]


CROSSREFS

Cf. A051588.
Sequence in context: A279448 A017897 A016311 * A016306 A021092 A219124
Adjacent sequences: A140958 A140959 A140960 * A140962 A140963 A140964


KEYWORD

easy,nonn


AUTHOR

Andy Fugard, Vladeta Jovovic, Jul 26 2008


STATUS

approved



