This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A112842 #4 Jun 01 2010 03:00:00 %S A112842 1,2,5,13,34,89,356,1737,9065,49610,325832,2795584,28098632,310726442, %T A112842 3877921669,58896208285,1083370353616,22901813128125,548749450880000, %U A112842 15471093192996501,522297110942557556,20691062026775504896 %N A112842 Number of domino tilings of a 9-pillow of order n. %C A112842 A 9-pillow is a generalized Aztec pillow. The 9-pillow of order n is a rotationally-symmetric region. It has a 2 X 2n central band of squares and then steps up from this band with steps of 9 horizontal squares to every 1 vertical square and steps down with steps of 1 horizontal square to every 1 vertical square. %D A112842 C. Hanusa (2005). A Gessel-Viennot-Type Method for Cycle Systems with Applications to Aztec Pillows. PhD Thesis. University of Washington, Seattle, USA. %e A112842 The number of domino tilings of the 9-pillow of order 8 is 9065=7^2*185. %Y A112842 A112842 breaks down as A112843^2 times A112844, where A112844 is not necessarily squarefree. %Y A112842 3-pillows: A112833-A112835; 5-pillows: A112836-A112838; 7-pillows: A112839-A112841. %K A112842 nonn %O A112842 0,2 %A A112842 Christopher Hanusa (chanusa(AT)math.binghamton.edu), Sep 21 2005