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 A060721 #12 Jul 02 2025 16:02:01
%S A060721 1,385,6569479,5421836400001,218857429741036363207,
%T A060721 432771509734663800164593788001,
%U A060721 41931064368881878511703371604583698172807
%N A060721 Singular n X n matrices over GF(7).
%H A060721 Harry J. Smith, <a href="/A060721/b060721.txt">Table of n, a(n) for n = 1..34</a>
%F A060721 For n >= 1, a(n) = 7^(n^2) - A053293(n) = 7^(n^2) - (7^n - 1)*(7^n - 7)*...*(7^n - 7^(n-1)).
%p A060721 for n from 1 to 15 do printf(`%d,`, 7^(n^2) - product(7^n-7^j, j=0..n-1)) od:
%o A060721 (PARI) a(n)={7^(n^2) - prod(j=0, n - 1, 7^n - 7^j)} \\ _Harry J. Smith_, Jul 10 2009
%Y A060721 Cf. A053293.
%K A060721 nonn
%O A060721 1,2
%A A060721 Avi Peretz (njk(AT)netvision.net.il), Apr 21 2001
%E A060721 More terms from _James Sellers_, Apr 24 2001