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A128902
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Number of degree n polynomials over GF(2) (with nonzero constant term) at Hamming distance 2 from some irreducible polynomial.
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0
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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
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OFFSET
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1,5
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LINKS
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EXAMPLE
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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.
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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