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 A167368 #16 Jan 12 2022 11:37:26 %S A167368 1,1,3,12,159120,6686252969760, %T A167368 89050715142739003008099466232718435351438398888454549774336000 %N A167368 a(n) = sigma((n!!)!). %F A167368 a(n) = A000203(A161563(n)). %t A167368 Array[DivisorSigma[1,#!!! ]&,7,1] %o A167368 (PARI) A167368(n)=sigma( prod(k=0,n\2-1,n-2*k) ! ) \\ _M. F. Hasler_, Feb 07 2011 %Y A167368 Cf. A062569, A167367. %K A167368 nonn,less %O A167368 0,3 %A A167368 _Vladimir Joseph Stephan Orlovsky_, Nov 01 2009 %E A167368 a(0)=1 prepended by _Alois P. Heinz_, Jan 12 2022