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 A065499 #9 Aug 03 2024 07:09:39
%S A065499 0,344,8451,176128,465125,8190720,6569479,90177536,166341033,
%T A065499 750016000,233671691,4193648640,878081581,14985313280,21730143375,
%U A065499 46170898432,7384597649,161217941760,17874835219,384008192000,414816720885
%N A065499 Noninvertible 3 X 3 matrices over Z_n.
%H A065499 T. D. Noe, <a href="/A065499/b065499.txt">Table of n, a(n) for n=1..1000</a>
%F A065499 a(n) = n^9 - A064767(n) = n^9 - n^9 * Product (1-1/p^3)*(1-1/p^2)*(1-1/p) where the product is over all the primes p that divide n.
%t A065499 f[n_] := (g = First[ Transpose[ FactorInteger[n]]]; n^9*(1 - Apply[ Times, 1 - 1/g] Apply[ Times, 1 - 1/g^2] Apply[ Times, 1 - 1/g^3])); Table[ f[n], {n, 1, 22} ]
%o A065499 (PARI) a(n) = {my(f = factor(n), p = f[,1], e=f[,2]); n^9 - prod(k = 1, #p, (p[k]-1)*(p[k]^2-1)*(p[k]^3-1)*(p[k]^(9*e[k]-6)));} \\ _Amiram Eldar_, Aug 03 2024
%Y A065499 Cf. A064767, A020479, A000252.
%K A065499 nonn
%O A065499 1,2
%A A065499 Dan Fux (dan.fux(AT)OpenGaia.com or danfux(AT)OpenGaia.com), Nov 25 2001
%E A065499 More terms from _Robert G. Wilson v_, Nov 30 2001