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 A280981 #10 Sep 08 2022 08:46:18
%S A280981 1,1,1,1,3,6,30,120,720,4320,38880,233280,2566080,25660800,282268800,
%T A280981 3104956800,46574352000,558892224000,9501167808000,133016349312000,
%U A280981 2261277938304000,40703002889472000,854763060678912000,13676208970862592000,300876597358977024000
%N A280981 Partial products of A049820; a(1) = a(2) = 1.
%F A280981 a(1) = a(2) = 1; for n>2, a(n) = Product_{i=3..n} A049820(i).
%t A280981 FoldList[#1 #2 &, Table[Boole[n <= 2] + n - DivisorSigma[0, n], {n, 25}]] (* _Michael De Vlieger_, Jan 11 2017 *)
%o A280981 (Magma) [1, 1] cat [&*[#[c: c in [1..k] | k mod c ne 0]: k in [3..n]]: n in [3..100]]
%Y A280981 Cf. A049820(n) = number of nondivisors of n.
%Y A280981 Cf. A049820, A161664.
%K A280981 nonn
%O A280981 1,5
%A A280981 _Jaroslav Krizek_, Jan 11 2017