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 A060869 #31 Dec 26 2024 18:11:07
%S A060869 3,75,1323,21675,348843,5589675,89467563,1431612075,22906317483,
%T A060869 366503176875,5864059218603,93824981052075,1501199831050923,
%U A060869 24019197833685675,384307167486454443,6148914688373205675,98382635048331029163,1574122160910735420075,25185954575121522535083
%N A060869 Number of n X n matrices over GF(4) with rank 1.
%H A060869 Harry J. Smith, <a href="/A060869/b060869.txt">Table of n, a(n) for n = 1..200</a>
%H A060869 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (21,-84,64).
%F A060869 a(n) = 1/3 * (4^n - 1)^2.
%F A060869 G.f.: -3*x*(4*x+1) / ((x-1)*(4*x-1)*(16*x-1)). - _Colin Barker_, Dec 23 2012
%F A060869 E.g.f.: exp(x)*(1 - 2*exp(3*x) + exp(15*x))/3. - _Stefano Spezia_, Dec 26 2024
%e A060869 a(2) = 75 because there are 76 (the second element in sequence A060716) singular 2 X 2 matrices over GF(4), that have rank <= 1 of which only the zero matrix has rank zero so a(2) = 76 - 1 = 75.
%o A060869 (PARI) a(n) = { (4^n - 1)^2 / 3 } \\ _Harry J. Smith_, Jul 13 2009
%Y A060869 Column k=4 of A379587.
%Y A060869 Cf. A060716.
%K A060869 nonn,easy
%O A060869 1,1
%A A060869 Ahmed Fares (ahmedfares(AT)my-deja.com), May 04 2001
%E A060869 More terms from Larry Reeves (larryr(AT)acm.org) and _Jason Earls_, May 07 2001
%E A060869 More terms from _Colin Barker_, Dec 23 2012