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 A208135 Numbers that match polynomials over {0,1} that have a factor containing a negative coefficient. 2
 9, 18, 21, 27, 33, 35, 36, 39, 42, 45, 49, 54, 57, 63, 65, 66, 70, 72, 75, 78, 84, 90, 93, 98, 99, 105, 108, 114, 126, 129, 130, 132, 133, 135, 140, 141, 144, 147, 150, 153, 155, 156, 159, 161, 165, 168, 175, 177, 180, 183, 186, 189, 195, 196, 198, 201 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The polynomials having coefficients in {0,1} are enumerated at A206073.  They include the following: p(1,x) = 1 p(2,x) = x p(3,x) = x + 1 p(9,x) = x^3 + 1 = (x + 1)(x^2 - x + 1) p(18,x) = x(x + 1)(x^2 - x + 1) p(33,x) = (x + 1)(x^4 - x^3 + x^2 - x + 1). A208135 gives those n for which p(n,x) has a factor containing a negative coefficient; A208136 is a subsequence of A208135 in which, for each p(n,x), there is a factor containing a negative coefficient, and that factor has not already occurred for some p(k,x) with k

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Last modified September 25 06:32 EDT 2020. Contains 337335 sequences. (Running on oeis4.)