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 A158335 A triangle of matrix polynomials: m(n)=antisymmeticmatix(n).Transpose[antisymmeticmatix(n)]. 0
 1, 0, -1, 1, -2, 1, 0, -9, 6, -1, 1, -12, 38, -12, 1, 0, -25, 100, -110, 20, -1, 1, -30, 255, -452, 255, -30, 1, 0, -49, 490, -1519, 1484, -511, 42, -1, 1, -56, 924, -3976, 6470, -3976, 924, -56, 1, 0, -81, 1512, -9324, 21816, -21942, 9240, -1548, 72, -1, 1, -90 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,5 COMMENTS Row sums are: {1, -1, 0, -4, 16, -16, 0, -64, 256, -256, 0,...}. Unsigned row sums are: {1, 1, 4, 16, 64, 256, 1024, 4096, 16384, 65536, 262144,...}. Example matrix is: M(3)={{2, -1, -1}, {-1, 2, -1}, {-1, -1, 2}} LINKS FORMULA m(n)=antisymmeticmatix(n).Transpose[antisymmeticmatix(n)]; out_(n,m)=coefficients(characteristicpolynomial(m(n),x),x). EXAMPLE {1}, {0, -1}, {1, -2, 1}, {0, -9, 6, -1}, {1, -12, 38, -12, 1}, {0, -25, 100, -110, 20, -1}, {1, -30, 255, -452, 255, -30, 1}, {0, -49, 490, -1519, 1484, -511, 42, -1}, {1, -56, 924, -3976, 6470, -3976, 924, -56, 1}, {0, -81, 1512, -9324, 21816, -21942, 9240, -1548, 72, -1}, {1, -90, 2445, -19320, 63090, -92252, 63090, -19320, 2445, -90, 1} MATHEMATICA Clear[M, T, d, a, x, a0]; T[n_, m_, d_] := If[ m < n, (-1)^(n + m), If[m > n, -(-1)^(n + m), 0]]; M[d_] := Table[T[n, m, d], {n, 1, d}, {m, 1, d}].Transpose[Table[T[n, m, d], {n, 1, d}, {m, 1, d}]]; Table[Det[M[d]], {d, 1, 10}]; Table[M[d], {d, 1, 10}] Table[CharacteristicPolynomial[M[d], x], {d, 1, 10}]; a = Join[{{1}}, Table[CoefficientList[Expand[CharacteristicPolynomial[M[ n], x]], x], {n, 1, 10}]]; Flatten[a]; Join[{1}, Table[Apply[Plus, CoefficientList[Expand[ CharacteristicPolynomial[M[n], x]], x]], {n, 1, 10}]]; CROSSREFS Sequence in context: A274740 A327350 A137452 * A111595 A021478 A115563 Adjacent sequences:  A158332 A158333 A158334 * A158336 A158337 A158338 KEYWORD sign,tabl,uned AUTHOR Roger L. Bagula, Mar 16 2009 STATUS approved

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Last modified September 17 12:26 EDT 2021. Contains 347477 sequences. (Running on oeis4.)