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Search: id:A086328
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| A086328 |
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Number of n X n circulant singular (0,1) matrices over the reals. |
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3
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| 1, 2, 2, 8, 2, 28, 2, 96, 62, 284, 2, 1504, 2, 3560, 2738, 16896, 2, 67636, 2, 235736, 109334, 707480, 2, 4376848, 206282, 10408792, 5417630, 48753784, 2, 212560504, 2, 739236864, 278770214, 2333737292, 133401818, 13837799440, 2
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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a(2*n+1) = A144926(2*n+1), n>0. a(2*p) = 2^p + binomial(2*p,p) if p is an odd prime, cf. A144926. [From Vladeta Jovovic (vladeta(AT)eunet.yu), Oct 02 2008]
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LINKS
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W. F. Lunnon, Table of n, a(n) for n = 0..39
W. F. Lunnon, C program for A144926 and A086328
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FORMULA
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a(n) = 2^n - A086323(n) . For a prime p, a(p) = 2 and the two circulants are those with all rows equal (0, 0, 0, ..., 0) or all rows equal (1, 1, 1, ..., 1).
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CROSSREFS
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Cf. A086323, A086324.
Sequence in context: A092694 A098984 A088560 this_sequence A095997 A056189 A121860
Adjacent sequences: A086325 A086326 A086327 this_sequence A086329 A086330 A086331
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KEYWORD
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nonn
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AUTHOR
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Yuval Dekel (dekelyuval(AT)hotmail.com), Aug 30 2003
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EXTENSIONS
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More terms from W. F. Lunnon, Oct 28 2008
a(0) removed, a(1) corrected by Max Alekseyev (maxale(AT)gmail.com), Sep 25 2009
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