# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a238558 Showing 1-1 of 1 %I A238558 #18 May 29 2017 21:11:51 %S A238558 1,3,4,1,3,8,1,6,18,1,6,36,32,13,1,9,64,128,87,1,9,100,308,332,1,12, %T A238558 146,647,1118,451,68,1,12,200,1160,3022,2756,824,1,15,264,1958,6882, %U A238558 10076,5009,1,15,336,3020,13798,28774,24237,4774,346 %N A238558 Number T(n,k) of equivalence classes of ways of placing k 3 X 3 tiles in an n X 8 rectangle under all symmetry operations of the rectangle; irregular triangle T(n,k), n>=3, 0<=k<=2*floor(n/3), read by rows. %H A238558 Andrew Howroyd, Table of n, a(n) for n = 3..971 %H A238558 Christopher Hunt Gribble, C++ program %e A238558 The first 8 rows of T(n,k) are: %e A238558 .\ k 0 1 2 3 4 5 6 %e A238558 n %e A238558 3 1 3 4 %e A238558 4 1 3 8 %e A238558 5 1 6 18 %e A238558 6 1 6 36 32 13 %e A238558 7 1 9 64 128 87 %e A238558 8 1 9 100 308 332 %e A238558 9 1 12 146 647 1118 451 68 %e A238558 10 1 12 200 1160 3022 2756 824 %o A238558 (C++) See Gribble link. %Y A238558 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, A238592. %K A238558 tabf,nonn %O A238558 3,2 %A A238558 _Christopher Hunt Gribble_, Feb 28 2014 %E A238558 Terms corrected and xrefs updated by _Christopher Hunt Gribble_, Apr 27 2015 %E A238558 Terms a(41) and beyond from _Andrew Howroyd_, May 29 2017 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE