cp's OEIS Frontend

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.

A092437 Triangle read by rows, arising from enumeration of domino tilings of Aztec Pillow-like regions.

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%I A092437 #11 Sep 01 2025 16:54:09
%S A092437 1,1,1,2,1,1,5,6,6,1,1,5,13,26,30,20,1,1,5,13,41,90,140,140,70,1,1,5,
%T A092437 13,41,121,302,560,742,630,252
%N A092437 Triangle read by rows, arising from enumeration of domino tilings of Aztec Pillow-like regions.
%C A092437 The rows are of lengths 1, 3, 5, 7, ...
%C A092437 Call the first row row 0 and entries starting from 0. Then entries i=0 through k in row k are A046717(i).
%C A092437 In row k, entry k+1 is sequence A092438 and entry k+2 is sequence A092439.
%C A092437 In row k, entry 2k-1 is A002457(k-1) and entry 2k is A000984(k).
%D A092437 James Propp, Enumeration of matchings: problems and progress, pp. 255-291 in L. J. Billera et al., eds, New Perspectives in Algebraic Combinatorics, Cambridge, 1999 (see Problem 13).
%H A092437 James Propp, <a href="http://faculty.uml.edu/jpropp/articles.html">Publications and Preprints</a>.
%H A092437 James Propp, Enumeration of matchings: problems and progress, in L. J. Billera et al. (eds.), <a href="http://www.msri.org/publications/books/Book38/contents.html">New Perspectives in Algebraic Combinatorics</a>.
%e A092437 Triangle begins:
%e A092437   1;
%e A092437   1, 1, 2;
%e A092437   1, 1, 5, 6, 6;
%e A092437   1, 1, 5, 13, 26, 30, 20;
%e A092437   ...
%Y A092437 Cf. A092438-A092443.
%K A092437 hard,nonn,tabf,more,changed
%O A092437 0,4
%A A092437 Christopher Hanusa (chanusa(AT)math.washington.edu), Mar 24 2004