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 A112838 #4 Jun 01 2010 03:00:00 %S A112838 1,2,5,13,13,29,34,100,130,305,361,881,1145,2906,3557,8669,10693, %T A112838 26893,33680,83360,102800,254565,317165,790037,980237,2428298,3011265, %U A112838 7483801,9301217,23092857,28646722,71093860 %N A112838 Small-number statistic from the enumeration of domino tilings of a 5-pillow of order n. %C A112838 A 5-pillow is a generalized Aztec pillow. The 5-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 5 horizontal squares to every 1 vertical square and steps down with steps of 1 horizontal square to every 1 vertical square. %C A112838 Plotting A112838(n+2)/A112838(n) gives an intriguing damped sine curve. %D A112838 C. Hanusa (2005). A Gessel-Viennot-Type Method for Cycle Systems with Applications to Aztec Pillows. PhD Thesis. University of Washington, Seattle, USA. %e A112838 The number of domino tilings of the 5-pillow of order 6 is 1666=7^2*34. A112838(n)=34. %Y A112838 A112833 breaks down as A112834^2 times A112835, where A112835 is not necessarily squarefree. %Y A112838 3-pillows: A112833-A112835; 7-pillows: A112839-A112841; 9-pillows: A112842-A112844. %K A112838 easy,nonn %O A112838 0,2 %A A112838 Christopher Hanusa (chanusa(AT)math.binghamton.edu), Sep 21 2005