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A238555 Number T(n,k) of equivalence classes of ways of placing k 2 X 2 tiles in an n X 7 rectangle under all symmetry operations of the rectangle; irregular triangle T(n,k), n>=2, 0<=k<=3*floor(n/2), read by rows. 21

%I #19 May 29 2017 21:17:15

%S 1,3,6,2,1,3,12,8,1,6,34,68,72,30,6,1,6,58,206,403,336,106,1,9,98,509,

%T 1551,2505,2196,971,219,20,1,9,140,980,4248,10592,15614,12876,5462,

%U 900,1,12,198,1742,9748,33644,73274,98779,80661,37886,9679,1258,72

%N Number T(n,k) of equivalence classes of ways of placing k 2 X 2 tiles in an n X 7 rectangle under all symmetry operations of the rectangle; irregular triangle T(n,k), n>=2, 0<=k<=3*floor(n/2), read by rows.

%H Andrew Howroyd, <a href="/A238555/b238555.txt">Table of n, a(n) for n = 2..953</a>

%H Christopher Hunt Gribble, <a href="/A238009/a238009_1.cpp.txt">C++ program</a>

%e The first 6 rows of T(n,k) are:

%e ./ k 0 1 2 3 4 5 6 7 8 9

%e n

%e 2 1 3 6 2

%e 3 1 3 12 8

%e 4 1 6 34 68 72 30 6

%e 5 1 6 58 206 403 336 106

%e 6 1 9 98 509 1551 2505 2196 971 219 20

%e 7 1 9 140 980 4248 10592 15614 12876 5462 900

%o (C++) See Gribble link.

%Y Cf. A034851, A226048, A102541, A226290, A238009, A228570, A225812, A238189, A238190, A228572, A228022, A231145, A231473, A231568, A232440, A228165, A238550, A238551, A238552, A228166, A238556, A228167, A238557, A238558, A238559, A228168, A238581, A238582, A238583, A228169, A238586, A238592.

%K tabf,nonn

%O 2,2

%A _Christopher Hunt Gribble_, Feb 28 2014

%E Terms corrected and xrefs updated by _Christopher Hunt Gribble_, Apr 27 2015

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Last modified March 29 07:27 EDT 2024. Contains 371265 sequences. (Running on oeis4.)