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 A128902 Number of degree n polynomials over GF(2) (with non-zero constant term) at Hamming distance 2 from some irreducible polynomial. 0
 0, 0, 0, 1, 2, 7, 14, 34, 72, 157, 326, 689, 1418, 2935, 6010, 12304, 25058, 51004, 103478, 209767, 424430, 858019, 1732430, 3495434, 7046432, 14196421, 28583424, 57522469, 115704938, 232645189, 467597246, 939526144 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,5 LINKS G. Lee, F. Ruskey and A. Williams, Hamming distance from irreducible polynomials over GF(2) EXAMPLE The coefficient vectors of the three degree 4 irreducible polynomials are 10011, 11111 and 11001. There is only one polynomial whose Hamming distance is two (or more) from all of them, namely 10101. Thus a(4) = |{10101}| = 1. CROSSREFS Sequence in context: A140253 A018453 A000147 * A227213 A060552 A191396 Adjacent sequences:  A128899 A128900 A128901 * A128903 A128904 A128905 KEYWORD nonn AUTHOR Frank Ruskey, Apr 22 2007 STATUS approved

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