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2, 8, 14, 20, 26, 32, 38, 44, 50, 56, 62, 68, 74, 80, 86, 92, 98, 104, 110, 116, 122, 128, 134, 140, 146, 152, 158, 164, 170, 176, 182, 188, 194, 200, 206, 212, 218, 224, 230, 236, 242, 248, 254, 260, 266, 272, 278, 284, 290, 296, 302, 308, 314, 320, 326
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,1
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COMMENTS
| Number of 3 X n binary matrices avoiding simultaneously the right angled numbered polyomino patterns (ranpp) (00;1), (01;0), (10;0) and (11;0). An occurrence of a ranpp (xy;z) in a matrix A=(a(i,j)) is a triple (a(i1,j1), a(i1,j2), a(i2,j1)) where i1<i2, j1<j2 and these elements are in same relative order as those in the triple (x,y,z). - Sergey Kitaev (kitaev(AT)ms.uky.edu), Nov 11 2004
A008615(a(n)) = n+1. - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Feb 27 2008
A157176(a(n)) = A013730(n). [From Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Feb 24 2009]
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LINKS
| Tanya Khovanova, Recursive Sequences
S. Kitaev, On multi-avoidance of right angled numbered polyomino patterns, Integers: Electronic Journal of Combinatorial Number Theory 4 (2004), A21, 20pp.
S. Kitaev, On multi-avoidance of right angled numbered polyomino patterns, University of Kentucky Research Reports (2004).
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FORMULA
| a(n)=2*(6*n-1)-a(n-1) (with a(0)=2) [From Vincenzo Librandi, Nov 20 2010]
G.f.: 2*(1+2*x)/(1-x)^2. [Colin Barker, Jan 08 2012]
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MAPLE
| a[1]:=2:for n from 2 to 100 do a[n]:=a[n-1]+6 od: seq(a[n], n=1..47); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Mar 16 2008
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MATHEMATICA
| Range[2, 500, 6] (* From Vladimir Joseph Stephan Orlovsky (4vladimir(AT)gmail.com), May 26 2011 *)
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PROG
| (Other) sage: [i+2 for i in range(280) if gcd(i, 6) == 6] # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), May 20 2009]
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CROSSREFS
| Cf. A008588, A016921, A016945, A016957, A016969.
Sequence in context: A105610 A117104 A082933 * A101959 A133229 A161330
Adjacent sequences: A016930 A016931 A016932 * A016934 A016935 A016936
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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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