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A099018 Number of 2 X n 0-1 matrices avoiding simultaneously the right angled numbered polyomino patterns (ranpp) (00;1), (01;0) and (01;1). 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 the same relative order as those in the triple (x,y,z). In general, the number of m X n 0-1 matrices in question is given by g.f. 2xy(y-xy+x-1)/((2x-1)(2y-1)(x+y-1)). 0
4, 10, 22, 46, 94, 190, 382, 766, 1534, 3070, 6142, 12286, 24574, 49150, 98302, 196606, 393214, 786430, 1572862, 3145726, 6291454, 12582910, 25165822, 50331646, 100663294, 201326590, 402653182, 805306366, 1610612734, 3221225470 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

Essentially a duplicate of A033484.

LINKS

S. Kitaev, On multi-avoidance of right angled numbered polyomino patterns, Integers: Electronic Journal of Combinatorial Number Theory 4 (2004), A21, 20pp.

FORMULA

G.f.: 2x(2-x)/((1-x)(1-2x))

3*2^n - 2.

a(n)=A033484(n). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Sep 02 2008]

a(n)=2*(a(n-1)+1) with a(1)=4 [From Vincenzo Librandi, Nov 17 2010]

CROSSREFS

Equals A007283(n) - 2.

Cf. m=3: A005803.

Sequence in context: A038621 A078407 A033484 * A008267 A056112 A118430

Adjacent sequences:  A099015 A099016 A099017 * A099019 A099020 A099021

KEYWORD

nonn

AUTHOR

Sergey Kitaev (kitaev(AT)ms.uky.edu), Nov 13 2004

EXTENSIONS

Corrected by T. D. Noe (noe(AT)sspectra.com), Nov 07 2006

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Last modified February 14 23:53 EST 2012. Contains 205689 sequences.