|
%I #18 May 29 2017 20:37:43
%S 1,3,2,1,3,4,1,6,9,1,6,21,13,4,1,9,39,53,23,1,9,64,128,87,1,12,95,283,
%T 311,91,10,1,12,133,521,891,543,106,1,15,177,917,2118,2030,646,1,15,
%U 228,1444,4424,6000,3295,456,25,1,18,285,2207,8408,15484,13106,4322,473
%N Number T(n,k) of equivalence classes of ways of placing k 3 X 3 tiles in an n X 7 rectangle under all symmetry operations of the rectangle; irregular triangle T(n,k), n>=3, 0<=k<=2*floor(n/3), read by rows.
%H Andrew Howroyd, <a href="/A238556/b238556.txt">Table of n, a(n) for n = 3..971</a>
%H Christopher Hunt Gribble, <a href="/A238009/a238009_1.cpp.txt">C++ program</a>
%e The first 5 rows of T(n,k) are:
%e ./ k 0 1 2 3 4 5 6
%e n
%e 3 1 3 2
%e 4 1 3 4
%e 5 1 6 9
%e 6 1 6 21 13 4
%e 7 1 9 39 53 23
%e 8 1 9 64 128 87
%e 9 1 12 95 283 311 91 10
%e 10 1 12 133 521 891 543 106
%e 11 1 15 177 917 2118 2030 646
%o (C++) See Gribble link.
%Y Cf. A034851, A226048, A102541, A226290, A238009, A228570, A225812, A238189, A238190, A228572, A228022, A231145, A231473, A231568, A232440, A228165, A238550-A238552, A228166, A238555, A228167, A238557-A238559, A228168, A238581-A238583, A228169, A238586, A238592.
%K tabf,nonn
%O 3,2
%A _Christopher Hunt Gribble_, Feb 28 2014
%E Terms corrected and xrefs updated by _Christopher Hunt Gribble_, Apr 27 2015
%E Terms a(48) and beyond by _Andrew Howroyd_, May 29 2017
|
