Search: id:A048489
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%I A048489
%S A048489 1,8,22,50,106,218,442,890,1786,3578,7162,14330,28666,57338,114682,
%T A048489 229370,458746,917498,1835002,3670010,7340026,14680058,29360122,
%U A048489 58720250,117440506,234881018,469762042,939524090,1879048186
%N A048489 7 * 2^n - 6.
%C A048489 Number of 3 X n 0-1 matrices avoiding simultaneously the right angled 
               numbered polyomino patterns (ranpp) (00;1), (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 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 2^(m+n)-2^m-2^n+2. 
               - Sergey Kitev (kitaev(AT)ms.uky.edu), Nov 13 2004
%C A048489 Row sums of triangle A131115.
%H A048489 S. Kitaev, <a href="http://www.integers-ejcnt.org/vol4.html">On multi-avoidance 
               of right angled numbered polyomino patterns</a>, Integers: Electronic 
               Journal of Combinatorial Number Theory 4 (2004), A21, 20pp.
%F A048489 Equals binomial transform of [1, 7, 7, 7,...] - Gary W. Adamson (qntmpkt(AT)yahoo.com), 
               Apr 28 2008
%F A048489 a(n) = A000079(n)*7-6 = A005009(n)-6. [From Omar E. Pol (info(AT)polprimos.com), 
               Dec 21 2008]
%t A048489 a[n_]:=7*2^n-6; ...and/or...a=1; lst={}; k=7; Do[a+=k; AppendTo[lst, 
               a]; k+=k, {n, 0, 5!}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), 
               Dec 16 2008]
%Y A048489 a(n)=T(6, n), array T given by A048483.
%Y A048489 n-th difference of a(n), a(n-1), ..., a(0) is (7, 7, 7, ...).
%Y A048489 Cf. A131115.
%Y A048489 Cf. A000079, A005009. [From Omar E. Pol (info(AT)polprimos.com), Dec 
               21 2008]
%Y A048489 Sequence in context: A069099 A145067 A112684 this_sequence A124701 A002968 
               A058404
%Y A048489 Adjacent sequences: A048486 A048487 A048488 this_sequence A048490 A048491 
               A048492
%K A048489 nonn
%O A048489 0,2
%A A048489 Clark Kimberling (ck6(AT)evansville.edu)

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