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Search: id:A073995
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| A073995 |
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Number of strings of length n over GF(4) with trace 0 and subtrace 0. |
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+0
5
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| 1, 1, 7, 28, 76, 256, 1072, 4288, 16576, 65536, 262912, 1051648, 4197376, 16777216, 67121152
(list; graph; listen)
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OFFSET
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1,3
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LINKS
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F. Ruskey Number of strings over GF(4) of given trace and subtrace
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FORMULA
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a(n; t, s) = a(n-1; t, s) + a(n-1; t-1, s-(t-1)) + a(n-1; t-2, s-2(t-2)) + a(n-1; t-3, s-3(t-3)) where t is the trace and s is the subtrace. Note that all operations involving operands t or s are carried out over GF(4).
G.f.: -q*(26*q^3+5*q-1-13*q^2)/[(1-2q)(1-4q)(1+4q^2)]. - Lawrence Sze, Oct 24 2004
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CROSSREFS
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Cf. A073996, A073997, A073998, A073999, A074000.
Sequence in context: A008457 A138503 A064951 this_sequence A061968 A024012 A163705
Adjacent sequences: A073992 A073993 A073994 this_sequence A073996 A073997 A073998
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KEYWORD
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easy,nonn
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AUTHOR
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Frank Ruskey, Nate Kube (fruskey(AT)cs.uvic.ca), Aug 16 2002
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