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.

A334456 Number h of points and of blocks of nontrivial biplanes.

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%I A334456 #19 May 06 2020 01:33:47
%S A334456 7,11,16,37,56,79,121
%N A334456 Number h of points and of blocks of nontrivial biplanes.
%C A334456 A biplane is an incidence structure consisting of a set P of h points and a set of h blocks, each of which is a k-subset of P (block size k), such that every pair of points lies in exactly 2 blocks (see Alavi et al.).
%H A334456 Seyed Hassan Alavi, Ashraf Daneshkhah, Cheryl E Praeger, <a href="https://arxiv.org/abs/2004.04535">Symmetries of biplanes</a>, arXiv:2004.04535 [math.GR], 2020. See Introduction p. 1.
%H A334456 P. Kaski and P. R. J. Östergård. <a href="https://doi.org/10.1002/jcd.20145">There are exactly five biplanes with k = 11</a>, J. Combin. Des., 16(2):117-127, 2008.
%Y A334456 Cf. A001109, A003409, A038723, A038725, A054490, A334457 (k).
%K A334456 nonn,more
%O A334456 1,1
%A A334456 _Stefano Spezia_, Apr 30 2020