cp's OEIS Frontend

A238557 Number T(n,k) of equivalence classes of ways of placing k 2 X 2 tiles in an n X 8 rectangle under all symmetry operations of the rectangle; irregular triangle T(n,k), n>=2, 0<=k<=4*floor(n/2), read by rows.

%I A238557 #20 May 29 2017 20:38:15
%S A238557 1,4,9,6,1,1,4,18,22,6,1,8,49,139,204,145,54,8,1,1,8,83,392,1056,1438,
%T A238557 956,240,25,1,12,139,927,3731,8772,12069,9506,4366,1160,179,16,1,1,12,
%U A238557 198,1742,9748,33644,73274,98779,80661,37886,9679,1258,72
%N A238557 Number T(n,k) of equivalence classes of ways of placing k 2 X 2 tiles in an n X 8 rectangle under all symmetry operations of the rectangle; irregular triangle T(n,k), n>=2, 0<=k<=4*floor(n/2), read by rows.
%H A238557 Andrew Howroyd, <a href="/A238557/b238557.txt">Table of n, a(n) for n = 2..991</a>
%H A238557 Christopher Hunt Gribble, <a href="/A238009/a238009_1.cpp.txt">C++ program</a>
%F A238557 tabf,nonn
%e A238557 The first 4 rows of T(n,k) are:
%e A238557 .\ k  0     1     2     3     4     5     6     7     8
%e A238557 n
%e A238557 2     1     4     9     6     1
%e A238557 3     1     4    18    22     6
%e A238557 4     1     8    49   139   204   145    54     8     1
%e A238557 5     1     8    83   392  1056  1438   956   240    25
%o A238557 (C++) See Gribble link.
%Y A238557 Cf. A034851, A226048, A102541, A226290, A238009, A228570, A225812, A238189, A238190, A228572, A228022, A231145, A231473, A231568, A232440, A228165, A238550-A238552, A228166, A238555, A238556, A228167, A238558, A238559, A228168, A238581-A238583, A228169, A238586, A238592.
%K A238557 tabf,nonn
%O A238557 2,2
%A A238557 _Christopher Hunt Gribble_, Feb 28 2014
%E A238557 Terms corrected and xrefs updated by _Christopher Hunt Gribble_, Apr 27 2015