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 A065498 #28 Jul 06 2025 02:54:17
%S A065498 1,2,288,1886976,489104179200,4755360379856486400,
%T A065498 1695944421638473850132889600,21967113634648374162210646578639667200,
%U A065498 10286692771039109536373764545035369981946101760000,173770439600109774111384717714984362383506603790098046648320000
%N A065498 Number of invertible n X n matrices mod 6 (i.e., over the ring Z_6).
%H A065498 Geoffrey Critzer, <a href="https://esirc.emporia.edu/handle/123456789/3595">Combinatorics of Vector Spaces over Finite Fields</a>, Master's thesis, Emporia State University, 2018.
%H A065498 Jeffrey Overbey, William Traves, and Jerzy Wojdylo, <a href="https://doi.org/10.1080/0161-110591893771">On the Keyspace of the Hill Cipher</a>, Cryptologia, Vol. 29, Iss. 1 (2005), pp. 59-72; <a href="http://jeff.over.bz/papers/undergrad/on-the-keyspace-of-the-hill-cipher.pdf">author's copy</a>.
%F A065498 a(n) = 6^(n^2) * Product_{k=1..n} ((1 - 1/2^k)(1 - 1/3^k)).
%F A065498 a(n) = A002884(n)*A053290(n). - _Geoffrey Critzer_, Jan 26 2018
%F A065498 a(n) ~ c * 6^(n^2), where c = A048651 * A100220 = 0.161757743053... . - _Amiram Eldar_, Jul 06 2025
%t A065498 a[n_] := 6^(n^2)*Product[(1 - 1/2^k)*(1 - 1/3^k), { k, 1, n} ]; Table[ a[n], {n, 0, 9} ]
%Y A065498 Column k=6 of A316622.
%Y A065498 Cf. A002884, A048651, A053290, A065128, A100220.
%K A065498 nonn,easy
%O A065498 0,2
%A A065498 Dan Fux (dan.fux(AT)OpenGaia.com or danfux(AT)OpenGaia.com), Nov 25 2001
%E A065498 More terms from _Robert G. Wilson v_, Nov 28 2001