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 A319366 #12 Sep 21 2018 21:56:43 %S A319366 1,127,14197,1527655,154708741,14581420567,1282928605477, %T A319366 106281575400295,8370106554738181,632240233746846007, %U A319366 46159332156459328357,3278558540783856976135,227767526682511220042821,15545657368091391819871447,1046175606578621216182684837 %N A319366 Number of 6 X n binary matrices such that any 2 rows have a common 1. %H A319366 Mathematics Stack Exchange, <a href="https://math.stackexchange.com/questions/2449509/an-interesting-combinatorics-problem">An interesting combinatorics problem</a> %H A319366 Quora, <a href="https://www.quora.com/How-many-ways-are-there-to-set-N-people-into-M-groups-so-that-every-two-groups-have-at-least-one-common-member">How many ways are there to set N people into M groups so that every two groups have at least one common member?</a> %F A319366 a(n) = 64^n - 15*48^n + 60*40^n - 15*36^n + 30*34^n - 6*33^n - 200*32^n - 180*30^n + 585*28^n + 45*27^n + 60*26^n + 150*25^n - 660*24^n - 360*23^n + 168*22^n - 585*21^n + 1245*20^n + 1665*19^n - 1965*18^n - 2100*17^n + 2170*16^n + 1325*15^n - 1770*14^n - 420*13^n + 1533*12^n - 1105*11^n + 435*10^n - 105*9^n + 15*8^n - 7^n (proved in the Quora answer). %Y A319366 Cf. A051587, A051588, A051589. %K A319366 nonn %O A319366 1,2 %A A319366 _T. V. Raziman_, Sep 17 2018