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.

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, 1551, 2505, 2196, 971, 219, 20, 1, 9, 140, 980, 4248, 10592, 15614, 12876, 5462, 900, 1, 12, 198, 1742, 9748, 33644, 73274, 98779, 80661, 37886, 9679, 1258, 72

Offset

2,2

Links

Andrew Howroyd, Table of n, a(n) for n = 2..953

Christopher Hunt Gribble, C++ program

Example

The first 6 rows of T(n,k) are:
./ k  0     1     2     3     4     5     6     7     8     9
n
2     1     3     6     2
3     1     3    12     8
4     1     6    34    68    72    30     6
5     1     6    58   206   403   336   106
6     1     9    98   509  1551  2505  2196   971   219    20
7     1     9   140   980  4248 10592 15614 12876  5462   900

Prog

(C++) See Gribble link.

Crossrefs

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.

Sequence in context: A058178 A058078 A016551 * A176034 A367729 A255051

Adjacent sequences: A238552 A238553 A238554 * A238556 A238557 A238558

Keyword

tabf,nonn

Author

Christopher Hunt Gribble, Feb 28 2014

Extensions

Terms corrected and xrefs updated by Christopher Hunt Gribble, Apr 27 2015

Status

approved