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 A355143 #28 Aug 24 2022 09:48:54
%S A355143 1,1,0,2,0,6,0,2,3,0,0,12,0,0,15,4,0,3,0,20,0,0,0,24,5,0,0,28,0,30,0,
%T A355143 4,0,0,35,6,0,0,0,40,0,42,0,0,45,0,0,48,7,5,0,0,0,54,0,56,0,0,0,60,0,
%U A355143 0,63,8,0,66,0,0,0,70,0,432,0,0,0,0,77,0,0,80
%N A355143 Product of middle divisors of n, or 0 if there are no middle divisors of n.
%e A355143 For n = 6 the middle divisors of 6 are 2 and 3, the product of them is 2*3 = 6, so a(6) = 6.
%e A355143 For n = 7 there are no middle divisors of 7, so a(7) = 0.
%e A355143 For n = 8 there is only one middle divisor of 8, the 2, so a(8) = 2.
%e A355143 For n = 72 the middle divisors of 72 are [6, 8, 9], the product of them is 6*8*9 = 432, so a(72) = 432.
%t A355143 a[n_] := If[(p = Product[If[Sqrt[n/2] <= d < Sqrt[2*n], d, 1], {d, Divisors[n]}]) == 1 && n > 2, 0, p]; Array[a, 100] (* _Amiram Eldar_, Jun 21 2022 *)
%o A355143 (PARI) a(n) = my(v=select(x->((x >= sqrt(n/2)) && (x < sqrt(n*2))), divisors(n))); if (#v, vecprod(v), 0); \\ _Michel Marcus_, Aug 04 2022
%Y A355143 Row products of A299761.
%Y A355143 Indices of zeros give A071561.
%Y A355143 Indices of nonzeros give A071562.
%Y A355143 Cf. A007955, A067742, A071090, A320142, A347950.
%K A355143 nonn
%O A355143 1,4
%A A355143 _Omar E. Pol_, Jun 20 2022
%E A355143 More terms from _Amiram Eldar_, Jun 21 2022