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 A231145 Number T(n,k) of equivalence classes of ways of placing k 2 X 2 tiles in an n X 5 rectangle under all symmetry operations of the rectangle; irregular triangle T(n,k), n>=2, 0<=k<=n-n%2, read by rows. 22
 1, 2, 2, 1, 2, 4, 1, 4, 13, 10, 4, 1, 4, 23, 35, 23, 1, 6, 40, 101, 125, 54, 10, 1, 6, 58, 206, 403, 336, 106, 1, 8, 83, 392, 1056, 1438, 956, 240, 25, 1, 8, 109, 641, 2281, 4424, 4718, 2409, 473, 1, 10, 142, 1011, 4429, 11370, 17252, 14478, 6094, 1020, 70 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,2 LINKS Andrew Howroyd, Table of n, a(n) for n = 2..967 (terms n=2..71 from Christopher Hunt Gribble) Christopher Hunt Gribble, C++ program EXAMPLE The first 8 rows of T(n,k) are: .\ k 0 1 2 3 4 5 6 7 8 n 2 1 2 2 3 1 2 4 4 1 4 13 10 4 5 1 4 23 35 23 6 1 6 40 101 125 54 10 7 1 6 58 206 403 336 106 8 1 8 83 392 1056 1438 956 240 25 9 1 8 109 641 2281 4424 4718 2409 473 PROG (C++) See Gribble link. CROSSREFS Cf. A034851, A226048, A102541, A226290, A238009, A228570, A225812, A238189, A238190, A228572, A228022, A231473, A231568, A232440, A228165, A238550, A238551, A238552, A228166, A238555, A238556, A228167, A238557, A238558, A238559, A228168, A238581, A238582, A238583, A228169, A238586, A238592. Sequence in context: A348178 A127677 A238009 * A344326 A007427 A048106 Adjacent sequences: A231142 A231143 A231144 * A231146 A231147 A231148 KEYWORD tabf,nonn AUTHOR Christopher Hunt Gribble, Feb 23 2014 EXTENSIONS Terms corrected and xrefs updated by Christopher Hunt Gribble, Apr 26 2015 STATUS approved

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Last modified December 2 16:37 EST 2023. Contains 367525 sequences. (Running on oeis4.)