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A090014
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Permanent of (0,1)-matrix of size n X (n+d) with d=4 and n-1 zeros not on a line.
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2
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5, 25, 155, 1135, 9545, 90445, 952175, 11016595, 138864365, 1893369505, 27756952355, 435287980375, 7269934161905, 128812336516885, 2413131201408695, 47652865538001595, 989254278781162325
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OFFSET
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1,1
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REFERENCES
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Brualdi, Richard A. and Ryser, Herbert J., Combinatorial Matrix Theory, Cambridge NY (1991), Chapter 7.
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LINKS
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FORMULA
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a(n) = (n+3)*a(n-1) + (n-2)*a(n-2), a(1)=5, a(2)=25.
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MATHEMATICA
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f[x_] := x*HypergeometricPFQ[{1, 5}, {}, x/(x+1)]/(x+1); Total /@ Partition[ CoefficientList[ Series[f[x], {x, 0, 18}], x], 2, 1] // Rest (* Jean-François Alcover, Nov 12 2013, after A001909 and Mark van Hoeij *)
t={5, 25}; Do[AppendTo[t, (n+3)*t[[-1]]+(n-2)*t[[-2]]], {n, 3, 17}]; t (* Indranil Ghosh, Feb 21 2017 *)
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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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EXTENSIONS
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STATUS
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approved
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