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 A349480 #16 Nov 20 2021 07:20:37
%S A349480 1,1,10,390,33456,4845360,1059099840,325460948400,133697543616000,
%T A349480 70733019878196480,46831083260349024000,37927830201482962540800,
%U A349480 36883442511877368877747200,42409212946187708288828160000
%N A349480 a(n) = Sum_{j=0..n} (-1)^(n-j) * Product_{k=(j-1)*n+1..j*n} k.
%H A349480 Seiichi Manyama, <a href="/A349480/b349480.txt">Table of n, a(n) for n = 0..214</a>
%F A349480 a(n) = n! * A349470(n) = n! * Sum_{k=0..n} (-1)^(n-k) * binomial(k*n,n).
%e A349480 a(2) = -1*2 + 3*4 = 10.
%e A349480 a(3) = 1*2*3 - 4*5*6 + 7*8*9 = 390.
%e A349480 a(4) = -1*2*3*4 + 5*6*7*8 - 9*10*11*12 + 13*14*15*16 = 33456.
%t A349480 a[n_] := n! * Sum[(-1)^(n - k) * Binomial[k*n, n], {k, 0, n}]; Array[a, 14, 0] (* _Amiram Eldar_, Nov 19 2021 *)
%o A349480 (PARI) a(n) = sum(j=0, n, (-1)^(n-j)*prod(k=(j-1)*n+1, j*n, k));
%Y A349480 Cf. A336513, A349470.
%K A349480 nonn
%O A349480 0,3
%A A349480 _Seiichi Manyama_, Nov 19 2021