A167011 - OEIS

%I #15 Jul 16 2015 10:18:51

%S 1,3,11,44,184,784,3363,14451,62097,266716,1145074,4914448,21087401,

%T 90472315,388129627,1665025084,7142592112,30639836360,131436162099,

%U 563822359859,2418629133001,10375190596724,44506436288882,190919170388912,818985577308225,3513200788519075

%N Number of Level 1 hexagonal polyominoes with cheesy blocks and n cells.

%C From Table 1, p.24, of Feretic. By level 0 cheesy polyominoes, and so too by level 0 polyominoes with cheesy blocks, Feretic appears to mean the usual column-convex polyominoes (A059716). See the paper for his definition.

%H Svjetlan Feretic, <a href="http://arxiv.org/abs/0910.4780">Polyominoes with nearly convex columns: A model with semidirected blocks</a>, Math. Commun. 15 (2010), 77--97, arXiv:0910.4780v1 [math.CO].

%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Polyhex_(mathematics)">Polyhex</a>

%H <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (9,-27,32,-13,3,1).

%F G.f.: x(-1+6x-11x^2+6x^3-2x^4)/(-1+9x-27x^2+32x^3-13x^4+3x^5+x^6).

%t LinearRecurrence[{9,-27,32,-13,3,1},{1,3,11,44,184,784},26] (* _Ray Chandler_, Jul 16 2015 *)

%t Rest[CoefficientList[Series[x*(-1+6x-11x^2+6x^3-2x^4)/(-1+9x-27x^2+32x^3-13x^4+3x^5+x^6),{x,0,26}],x]] (* _Ray Chandler_, Jul 16 2015 *)

%Y Cf. A059716, A167012, A167013.

%K nonn,easy

%O 1,2

%A _Jonathan Vos Post_, Oct 26 2009

%E Edited by _Ralf Stephan_, Feb 07 2014