cp's OEIS Frontend

A231145 Number T(n,k) of equivalence classes of ways of placing k 2 X 2 tiles in an n X 5 rectangle under all symmetry operations of the rectangle; irregular triangle T(n,k), n>=2, 0<=k<=n-n%2, read by rows.

%I A231145 #33 May 29 2017 21:28:59
%S A231145 1,2,2,1,2,4,1,4,13,10,4,1,4,23,35,23,1,6,40,101,125,54,10,1,6,58,206,
%T A231145 403,336,106,1,8,83,392,1056,1438,956,240,25,1,8,109,641,2281,4424,
%U A231145 4718,2409,473,1,10,142,1011,4429,11370,17252,14478,6094,1020,70
%N A231145 Number T(n,k) of equivalence classes of ways of placing k 2 X 2 tiles in an n X 5 rectangle under all symmetry operations of the rectangle; irregular triangle T(n,k), n>=2, 0<=k<=n-n%2, read by rows.
%H A231145 Andrew Howroyd, <a href="/A231145/b231145.txt">Table of n, a(n) for n = 2..967</a> (terms n=2..71 from Christopher Hunt Gribble)
%H A231145 Christopher Hunt Gribble, <a href="/A238009/a238009_1.cpp.txt">C++ program</a>
%e A231145 The first 8 rows of T(n,k) are:
%e A231145 .\ k  0     1     2     3     4     5     6     7     8
%e A231145 n
%e A231145 2     1     2     2
%e A231145 3     1     2     4
%e A231145 4     1     4    13    10     4
%e A231145 5     1     4    23    35    23
%e A231145 6     1     6    40   101   125    54    10
%e A231145 7     1     6    58   206   403   336   106
%e A231145 8     1     8    83   392  1056  1438   956   240    25
%e A231145 9     1     8   109   641  2281  4424  4718  2409   473
%o A231145 (C++) See Gribble link.
%Y A231145 Cf. A034851, A226048, A102541, A226290, A238009, A228570, A225812, A238189, A238190, A228572, A228022, A231473, A231568, A232440, A228165, A238550, A238551, A238552, A228166, A238555, A238556, A228167, A238557, A238558, A238559, A228168, A238581, A238582, A238583, A228169, A238586, A238592.
%K A231145 tabf,nonn
%O A231145 2,2
%A A231145 _Christopher Hunt Gribble_, Feb 23 2014
%E A231145 Terms corrected and xrefs updated by _Christopher Hunt Gribble_, Apr 26 2015