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 A086699 #17 Dec 15 2024 19:49:20 %S A086699 1,9,294,37800,19373760,39687459840,325139829719040, %T A086699 10654345790226432000,1396491759480328106803200, %U A086699 732164571206732295657278668800,1535460761275478347250381697633484800,12880379193826999985837000446453418557440000 %N A086699 Number of n X n matrices over GF(2) with rank n-1. %C A086699 a(n)/2^(n^2) is the probability that a random linear operator T on an n dimensional vector space over the field with two elements is such that the dimension of the range of T equals n-1. This probability is Product{j>=2} 1 - 1/2^j which is 2 times the probability that the dimension of the range of T equals n. Cf. A048651. - _Geoffrey Critzer_, Jun 28 2017 %H A086699 Vincenzo Librandi, <a href="/A086699/b086699.txt">Table of n, a(n) for n = 1..58</a> %F A086699 for n>=2 : a(n) = product j=0...n-2 (2^n - 2^j)^2 / (2^(n-1)- 2^j). %t A086699 Table[Product[(q^n - q^i)^2/(q^(n - 1) - q^i), {i, 0, n - 2}] /. q -> 2, {n, 0, 15}] (* _Geoffrey Critzer_, Jun 28 2017 *) %o A086699 (PARI) a(n) = prod(j=0, n-2, (2^n - 2^j)^2 / (2^(n-1)- 2^j)); \\ _Michel Marcus_, Jun 28 2017 %Y A086699 Cf. A002884, A060867. %K A086699 nonn %O A086699 1,2 %A A086699 Yuval Dekel (dekelyuval(AT)hotmail.com), Jul 28 2003 %E A086699 More terms from _David Wasserman_, Mar 28 2005