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A054719
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Number of 4-ary sequences with primitive period n.
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6
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1, 4, 12, 60, 240, 1020, 4020, 16380, 65280, 262080, 1047540, 4194300, 16772880, 67108860, 268419060, 1073740740, 4294901760, 17179869180, 68719210560, 274877906940, 1099510578960, 4398046494660, 17592181850100, 70368744177660
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| Equivalently, output sequences with primitive period n from a simple cycling shift register.
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REFERENCES
| E. N. Gilbert and J. Riordan, Symmetry types of periodic sequences, Illinois J. Math., 5 (1961), 657-665.
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FORMULA
| Sum mu(d)*4^(n/d); d|n.
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MAPLE
| A054719 := proc(n) local d, s; if n = 0 then RETURN(1); else s := 0; for d in divisors(n) do s := s+mobius(d)*4^(n/d); od; RETURN(s); fi; end;
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CROSSREFS
| Cf. A001868, A027377.
Sequence in context: A051858 A084709 A057394 * A083484 A097250 A088860
Adjacent sequences: A054716 A054717 A054718 * A054720 A054721 A054722
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), Apr 20 2000
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