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A060871
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Number of n X n matrices over GF(7) with rank 1.
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1
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6, 384, 19494, 960000, 47073606, 2306841984, 113036904294, 5538819840000, 271402252867206, 13298710955443584, 651636840771389094, 31930205225480640000, 1564580056242329380806, 76664422757230585805184
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OFFSET
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1,1
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LINKS
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FORMULA
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a(n) = 1/6 * (7^n - 1)^2.
G.f.: -6*x*(7*x+1) / ((x-1)*(7*x-1)*(49*x-1)). [Colin Barker, Dec 23 2012]
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EXAMPLE
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a(2) = 384 because there are 385 (the second element in sequence A060721) singular 2 X 2 matrices over GF(7), that have rank <= 1 of which only the zero matrix has rank zero so a(2) = 385 - 1 = 384.
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PROG
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(PARI) { for (n=1, 200, write("b060871.txt", n, " ", (7^n - 1)^2 / 6); ) } \\ Harry J. Smith, Jul 13 2009
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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Ahmed Fares (ahmedfares(AT)my-deja.com), May 04 2001
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EXTENSIONS
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More terms from Larry Reeves (larryr(AT)acm.org), May 07 2001
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STATUS
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approved
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