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 A103407 Triangle of absolute values of the coefficients (in descending powers) of the characteristic polynomials of n X n matrices with 3's on the main diagonal and 1's elsewhere. 1
 1, 1, 3, 1, 6, 8, 1, 9, 24, 20, 1, 12, 48, 80, 48, 1, 15, 80, 200, 240, 112, 1, 18, 120, 400, 720, 672, 256, 1, 21, 168, 700, 1680, 2352, 1792, 576, 1, 24, 224, 1120, 3360, 6272, 7168, 4608, 1280, 1, 27, 288, 1680, 6048, 14112, 21504, 20736, 11520, 2816, 1, 30 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS EXAMPLE 3rd row (1, 9, 24, 20) with alternating signs = characteristic polynomial 3 X 3 matrix [3 1 1 / 1 3 1 / 1 1 3], x^3 - 9x^2 + 24x - 20. CROSSREFS Row sums are A006234: 1, 4, 15, 54, 189... Rightmost terms in each row = A001792: 1, 3, 8, 20, 48, 112, 256...(row sums of A103406, the analogous triangle with all 2's in the generating matrix.) See A103247 for another version. Sequence in context: A199662 A280293 A226483 * A306938 A257259 A074475 Adjacent sequences:  A103404 A103405 A103406 * A103408 A103409 A103410 KEYWORD nonn,tabl AUTHOR Gary W. Adamson, Feb 04 2005 EXTENSIONS Extended and edited by John W. Layman, Mar 17 2005 STATUS approved

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Last modified June 17 19:10 EDT 2019. Contains 324198 sequences. (Running on oeis4.)