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A174647
Determinant of the matrix a(i,j) = 1 if Abs(i-j) <2 and -1 in the rest.
0
-4, 0, 0, 0, -64, 0, 256, 1024, 0, -4096, -12288, 0, 49152, 131072, 0, -524288, -1310720, 0, 5242880, 12582912, 0, -50331648, -117440512, 0, 469762048, 1073741824, 0, -4294967296, -9663676416, 0, 38654705664, 85899345920, 0
OFFSET
3,1
FORMULA
Empirical g.f.: -4*x^3*(8*x^3+4*x^2-2*x+1) / ((2*x+1)*(4*x^2-2*x+1)^2). - Colin Barker, Jun 20 2013
EXAMPLE
Det({ {1, 1, -1, -1, -1, -1, -1}, {1, 1, 1, -1, -1, -1, -1}, {-1, 1, 1, 1, -1, -1, -1}, {-1, -1, 1, 1, 1, -1, -1}, {-1, -1, -1, 1, 1, 1, -1}, {-1, -1, -1, -1, 1, 1, 1}, {-1, -1, -1, -1, -1, 1, 1} }=-64 => a(7)=-64
CROSSREFS
Sequence in context: A057386 A099306 A228630 * A258644 A169770 A287633
KEYWORD
sign
AUTHOR
STATUS
approved