A238583 - OEIS

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A238583

Number T(n,k) of equivalence classes of ways of placing k 4 X 4 tiles in an n X 9 rectangle under all symmetry operations of the rectangle; irregular triangle T(n,k), n>=4, 0<=k<=2*floor(n/4), read by rows.

21

1, 3, 2, 1, 3, 4, 1, 6, 9, 1, 6, 14, 1, 9, 32, 18, 4, 1, 9, 55, 65, 23, 1, 12, 91, 164, 87, 1, 12, 132, 320, 229, 1, 15, 186, 608, 648, 134, 10, 1, 15, 245, 1043, 1633, 770, 106, 1, 18, 317, 1736, 3659, 2800, 646, 1, 18, 394, 2666, 7247, 7572, 2510

(list; graph; refs; listen; history; text; internal format)

OFFSET

4,2

LINKS

Andrew Howroyd, Table of n, a(n) for n = 4..992

Christopher Hunt Gribble, C++ program

EXAMPLE

The first 8 rows of T(n,k) are:

.\ k 0 1 2 3 4

n

4 1 3 2

5 1 3 4

6 1 6 9

7 1 6 14

8 1 9 32 18 4

9 1 9 55 65 23

10 1 12 91 164 87

11 1 12 132 320 229

PROG

(C++) See program 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, A238582, A228169, A238586, A238592

Sequence in context: A010267 A023636 A205838 * A238556 A102288 A081248

Adjacent sequences: A238580 A238581 A238582 * A238584 A238585 A238586

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(26) and beyond from Andrew Howroyd, May 29 2017

STATUS

approved