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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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..21.

Andy Fugard, Counting first-order models (with n individuals) of syllogisms.

Index entries for linear recurrences with constant coefficients, signature (19,-118,240).

FORMULA

a(n) = 8^n-2*6^n+5^n.

G.f.: x*(2*x-1)/((5*x-1)*(6*x-1)*(8*x-1)). [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

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Last modified September 20 02:20 EDT 2019. Contains 327207 sequences. (Running on oeis4.)