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 A384166 #19 May 22 2025 16:41:11
%S A384166 1,3,60,1989,92160,5486535,399072960,34298042625,3400783626240,
%T A384166 382128386114475,47986411423104000,6659996213472126525,
%U A384166 1012334387351519232000,167253493686752981883375,29842935065036371998720000,5719198821953333723419037625,1171620424982972483984424960000
%N A384166 a(n) = Product_{k=0..n-1} (3*n+4*k).
%H A384166 Vincenzo Librandi, <a href="/A384166/b384166.txt">Table of n, a(n) for n = 0..200</a>
%F A384166 a(n) = 4^n * RisingFactorial(3*n/4,n).
%F A384166 a(n) = n! * [x^n] 1/(1 - 4*x)^(3*n/4).
%F A384166 a(n) = (3/7) * 4^n * n! * binomial(7*n/4,n) for n > 0.
%t A384166 a[n_]:=Product[(3*n+4*k),{k,0,n-1}];Table[a[n],{n,0,15}] (* _Vincenzo Librandi_, May 22 2025 *)
%o A384166 (PARI) a(n) = prod(k=0, n-1, 3*n+4*k);
%o A384166 (Sage)
%o A384166 def a(n): return 4^n*rising_factorial(3*n/4, n)
%o A384166 (Python)
%o A384166 from math import prod
%o A384166 def A384166(n): return prod(3*n+i for i in range(0,n<<2,4)) # _Chai Wah Wu_, May 21 2025
%o A384166 (Magma) [1] cat [&*[(3*n + 4*k): k in [0..n-1]]: n in [1..16]]; // _Vincenzo Librandi_, May 22 2025
%Y A384166 Cf. A384164, A384165.
%Y A384166 Cf. A303487.
%K A384166 nonn,easy
%O A384166 0,2
%A A384166 _Seiichi Manyama_, May 21 2025