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.

A212438 Irregular triangle read by rows: T(n,k) is the number of polyhedra with n faces and k vertices (n >= 4, k=4..2n-4).

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%I A212438 #26 Mar 27 2021 22:49:40
%S A212438 1,0,1,1,0,1,2,2,2,0,0,2,8,11,8,5,0,0,2,11,42,74,76,38,14,0,0,0,8,74,
%T A212438 296,633,768,558,219,50,0,0,0,5,76,633,2635,6134,8822,7916,4442,1404,
%U A212438 233,0,0,0,0,38,768,6134,25626,64439,104213,112082,79773,36528,9714,1249
%N A212438 Irregular triangle read by rows: T(n,k) is the number of polyhedra with n faces and k vertices (n >= 4, k=4..2n-4).
%C A212438 Because of duality, T(n,k) = T(k,n). - _Ivan Neretin_, May 25 2016
%C A212438 The number of edges is n+k-2. - _Andrew Howroyd_, Mar 27 2021
%H A212438 Andrew Howroyd, <a href="/A212438/b212438.txt">Table of n, a(n) for n = 4..199</a> (rows 4..17)
%H A212438 Gunnar Brinkmann and Brendan McKay, <a href="https://users.cecs.anu.edu.au/~bdm/papers/plantri-full.pdf">Fast generation of planar graphs (expanded edition)</a>, Table 9-11.
%H A212438 G. P. Michon, <a href="http://www.numericana.com/data/polyhedra.htm">Counting Polyhedra</a>
%e A212438 Triangle begins:
%e A212438 1
%e A212438 0 1 1
%e A212438 0 1 2  2  2
%e A212438 0 0 2  8 11   8    5
%e A212438 0 0 2 11 42  74   76   38   14
%e A212438 0 0 0  8 74 296  633  768  558  219   50
%e A212438 0 0 0  5 76 633 2635 6134 8822 7916 4442 1404 233
%e A212438 ...
%Y A212438 A049337, A058787, A212438 are all versions of the same triangle.
%Y A212438 Row sums (the same as column sums) are A000944.
%Y A212438 Main diagonal is A002856.
%Y A212438 Cf. A002840 (by edges), A239893.
%K A212438 nonn,tabf
%O A212438 4,7
%A A212438 _N. J. A. Sloane_, May 16 2012
%E A212438 Terms a(53) and beyond from _Andrew Howroyd_, Mar 27 2021