Wieferich pairs and Barker sequences
Wieferich pairs and Barker sequences
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DOI:
10.1007/s10623-009-9301-3
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发表时间:
2009-12
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通讯作者:
Michael J. Mossinghoff
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作者:
Michael J. Mossinghoff
We show that if a Barker sequence of lengthn> 13 exists, then eithern= 189 260 468 001 034 441 522 766 781 604, orn> 2 · 1030. This improves the lower bound on the length of a long Barker sequence by a factor of more than 107. We also show that all but fewer than 1600 integersn≤ 4 · 1026can be eliminated as the order of a circulant Hadamard matrix. These results are obtained by completing extensive searches for Wieferich prime pairs (q,p), which are defined by the relationmodp2, and analyzing their results in combination with a number of arithmetic restrictions onn.