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A008576
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Coordination sequence for planar net 4.8.8.
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2
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1, 3, 5, 8, 11, 13, 16, 19, 21, 24, 27, 29, 32, 35, 37, 40, 43, 45, 48, 51, 53, 56, 59, 61, 64, 67, 69, 72, 75, 77, 80, 83, 85, 88, 91, 93, 96, 99, 101, 104, 107, 109, 112, 115, 117, 120, 123, 125, 128, 131, 133
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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REFERENCES
| Meier and Moeck, Topology of 3-D 4-connected nets ..., J. Solid State Chem 27 1979 349-355, esp. p. 351.
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LINKS
| T. D. Noe, Table of n, a(n) for n=0..1000
Index to sequences with linear recurrences with constant coefficients, signature (1,0,1,-1).
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FORMULA
| G.f.: [(1+x)^2(1+x^2)]/[(1-x)^2(1+x+x^2)]. - R. Stephan, Apr 24 2004
Sum of alternate terms of A042965 (numbers not congruent to 2 mod 4), such that A042965(n) = A042965(n+1) + A042965(n-1). - Gary W. Adamson (qntmpkt(AT)yahoo.com), Sep 12 2007
a(0)=1, a(1)=3, a(2)=5, a(3)=8, a(4)=11, a(n)=a(n-1)+a(n-3)-a(n-4) [From Harvey P. Dale, Nov 24 2011]
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MAPLE
| if n mod 3 = 0 then 8*n/3 elif n mod 3 = 1 then 8*(n-1)/3+3 else 8*(n-2)/3+5 fi;
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MATHEMATICA
| cspn[n_]:=Module[{c=Mod[n, 3]}, Which[c==0, (8n)/3, c==1, (8(n-1))/3+3, True, (8(n-2))/3+5]]; Join[{1}, Array[cspn, 50]] (* or *) Join[{1}, LinearRecurrence[ {1, 0, 1, -1}, {3, 5, 8, 11}, 50]] (* From Harvey P. Dale, Nov 24 2011 *)
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CROSSREFS
| Cf. A042965.
Sequence in context: A026274 A137910 A022850 * A047622 A079392 A022852
Adjacent sequences: A008573 A008574 A008575 * A008577 A008578 A008579
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KEYWORD
| nonn,easy
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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