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 A112841 #4 Jun 01 2010 03:00:00 %S A112841 1,2,5,13,34,34,74,73,193,256,793,1049,2465,2857,6577,8226,21348, %T A112841 28872,74740,91970,222217,268769,669265,852305,2201945,2805760, %U A112841 7000777,8636081,21311098,26588770,67091170,85150213 %N A112841 Small-number statistic from the enumeration of domino tilings of a 7-pillow of order n. %C A112841 A 7-pillow is a generalized Aztec pillow. The 7-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 7 horizontal squares to every 1 vertical square and steps down with steps of 1 horizontal square to every 1 vertical square. %C A112841 Plotting A112841(n+2)/A112841(n) gives an intriguing damped sine curve. %D A112841 C. Hanusa (2005). A Gessel-Viennot-Type Method for Cycle Systems with Applications to Aztec Pillows. PhD Thesis. University of Washington, Seattle, USA. %e A112841 The number of domino tilings of the 7-pillow of order 8 is 23353=11^2*193. A112841(n)=193. %Y A112841 A112839 breaks down as A112840^2 times A112841, where A112841 is not necessarily squarefree. %Y A112841 3-pillows: A112833-A112835; 5-pillows: A112836-A112838; 9-pillows: A112842-A112844. %K A112841 easy,nonn %O A112841 0,2 %A A112841 Christopher Hanusa (chanusa(AT)math.binghamton.edu), Sep 21 2005