cp's OEIS Frontend

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.

%I A238555 #19 May 29 2017 21:17:15
%S A238555 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 A238555 1551,2505,2196,971,219,20,1,9,140,980,4248,10592,15614,12876,5462,
%U A238555 900,1,12,198,1742,9748,33644,73274,98779,80661,37886,9679,1258,72
%N 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.
%H A238555 Andrew Howroyd, <a href="/A238555/b238555.txt">Table of n, a(n) for n = 2..953</a>
%H A238555 Christopher Hunt Gribble, <a href="/A238009/a238009_1.cpp.txt">C++ program</a>
%e A238555 The first 6 rows of T(n,k) are:
%e A238555 ./ k  0     1     2     3     4     5     6     7     8     9
%e A238555 n
%e A238555 2     1     3     6     2
%e A238555 3     1     3    12     8
%e A238555 4     1     6    34    68    72    30     6
%e A238555 5     1     6    58   206   403   336   106
%e A238555 6     1     9    98   509  1551  2505  2196   971   219    20
%e A238555 7     1     9   140   980  4248 10592 15614 12876  5462   900
%o A238555 (C++) See Gribble link.
%Y A238555 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 A238555 tabf,nonn
%O A238555 2,2
%A A238555 _Christopher Hunt Gribble_, Feb 28 2014
%E A238555 Terms corrected and xrefs updated by _Christopher Hunt Gribble_, Apr 27 2015