A238592 Number T(n,k) of equivalence classes of ways of placing k 3 X 3 tiles in an n X 10 rectangle under all symmetry operations of the rectangle; irregular triangle T(n,k), n>=3, 0<=k<=3*floor(n/3), read by rows.

1, 4, 9, 2, 1, 4, 18, 8, 1, 8, 42, 28, 1, 8, 77, 165, 151, 44, 6, 1, 12, 133, 521, 891, 543, 106, 1, 12, 200, 1160, 3022, 2756, 824, 1, 16, 288, 2260, 8443, 13336, 9364, 2819, 387, 20, 1, 16, 387, 3867, 19833, 48418, 58731, 34797, 9462, 900

Offset

3,2

Links

Andrew Howroyd, Table of n, a(n) for n = 3..989

Christopher Hunt Gribble, C++ program

Example

The first 6 rows of T(n,k) are:
.\ k    0      1      2      3      4      5      6
n
3       1      4      9      2
4       1      4     18      8
5       1      8     42     28
6       1      8     77    165    151     44      6
7       1     12    133    521    891    543    106
8       1     12    200   1160   3022   2756    824

Prog

(C++) See Gribble link.

Crossrefs

Cf. A034851, A226048, A102541, A226290, A238009, A228570, A225812, A238189, A238190, A228572, A228022, A231145, A231473, A231568, A232440, A228165, A238550-A238552, A228166, A238555, A238556, A228167, A238557-A238559, A228168, A238581-A238583, A228169, A238586.

Sequence in context: A032760 A129970 A006830 * A229553 A254061 A098174

Adjacent sequences: A238589 A238590 A238591 * A238593 A238594 A238595

Keyword

tabf,nonn

Author

Christopher Hunt Gribble, Mar 01 2014

Extensions

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

Terms a(36) and beyond from Andrew Howroyd, May 29 2017

Status

approved