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 A114778 #11 Feb 16 2025 08:33:00
%S A114778 1,1,2,6,24,240,4320,120960,9676800,1567641600,438939648000,
%T A114778 386266890240000,750902834626560000,2733286318040678400000,
%U A114778 33674087438261157888000000,981936389699695364014080000000
%N A114778 Cumulative product of triple factorial A007661.
%C A114778 This is the product analog of what for sums is A114347.
%H A114778 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Multifactorial.html">Multifactorial.</a>
%F A114778 a(n) = Product_{j=0..n} j!!!. a(n) = Product_{j=0..n} A007661(j). a(n) = n!!! * a(n-1) where a(0) = 1, a(1) = 1 and n >= 2. a(n) = n*(n-3)!!! * a(n-1) where a(0) = 1, a(1) = 1, a(2) = 2 and n >= 3.
%e A114778 a(10) = 1!!! * 2!!! * 3!!! * 4!!! * 5!!! * 6!!! * 7!!! * 8!!! * 9!!! * 10!!!
%e A114778 = 1 * 2 * 3 * 4 * 10 * 18 * 28 * 80 * 162 * 280 = 438939648000 = 2^15 * 3^7 * 5^3 * 7^2.
%Y A114778 Cf. A006882, A000178, A114347.
%K A114778 easy,nonn
%O A114778 0,3
%A A114778 _Jonathan Vos Post_, Feb 18 2006