%I #19 May 29 2017 21:10:17

%S 1,3,2,1,3,4,1,6,9,1,6,14,1,9,32,18,4,1,9,55,65,23,1,12,91,164,87,1,

%T 12,132,320,229,1,15,186,608,648,134,10,1,15,245,1043,1633,770,106,1,

%U 18,317,1736,3659,2800,646,1,18,394,2666,7247,7572,2510

%N Number T(n,k) of equivalence classes of ways of placing k 4 X 4 tiles in an n X 9 rectangle under all symmetry operations of the rectangle; irregular triangle T(n,k), n>=4, 0<=k<=2*floor(n/4), read by rows.

%H Andrew Howroyd, <a href="/A238583/b238583.txt">Table of n, a(n) for n = 4..992</a>

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

%e The first 8 rows of T(n,k) are:

%e .\ k 0 1 2 3 4

%e n

%e 4 1 3 2

%e 5 1 3 4

%e 6 1 6 9

%e 7 1 6 14

%e 8 1 9 32 18 4

%e 9 1 9 55 65 23

%e 10 1 12 91 164 87

%e 11 1 12 132 320 229

%o (C++) See program link.

%Y Cf. A034851, A226048, A102541, A226290, A238009, A228570, A225812, A238189, A238190, A228572, A228022, A231145, A231473, A231568, A232440, A228165, A238550-A238552, A228166, A238555, A238556, A228167, A238557-A238559, A228168, A238581, A238582, A228169, A238586, A238592

%K tabf,nonn

%O 4,2

%A _Christopher Hunt Gribble_, Mar 01 2014

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

%E Terms a(26) and beyond from _Andrew Howroyd_, May 29 2017