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A342805 a(n) = (1/n)*(product of the terms of the n-th row of A177028).

%I A342805 #12 Mar 24 2021 06:04:49
%S A342805 1,1,1,3,1,1,4,3,1,5,1,1,18,4,1,7,1,1,24,5,1,9,4,1,10,18,1,11,1,1,12,
%T A342805 7,5,156,1,1,14,8,1,15,1,1,288,9,1,17,4,1,90,10,1,19,21,1,20,11,1,21,
%U A342805 1,1,22,48,8,414,1,1,24,65,1,25,1,1,234,14,1,81,1,1,784,15
%N A342805 a(n) = (1/n)*(product of the terms of the n-th row of A177028).
%H A342805 Michel Marcus, <a href="/A342805/b342805.txt">Table of n, a(n) for n = 3..10000</a>
%F A342805 For m in A090466, a(m) > 1.
%F A342805 For m in A090467, a(m) = 1.
%e A342805 For n=3, A177028 row is (3), so a(3) = 3/3 = 1.
%e A342805 For n=6, A177028 row is (6, 3), so a(6) = 6*3/6 = 3.
%e A342805 For n=15, A177028 row is (15, 6, 3), so a(15) = 15*6*3/15 = 18.
%o A342805 (PARI) row(n)=my(v=List()); fordiv(2*n, k, if(k<2, next); if(k==n, break); my(s=(2*n/k-4+2*k)/(k-1)); if(denominator(s)==1, listput(v, s))); Vec(v); \\ A177028
%o A342805 a(n) = vecprod(row(n))/n;
%Y A342805 Cf. A090466, A090467, A177028, A342772.
%K A342805 nonn
%O A342805 3,4
%A A342805 _Michel Marcus_, Mar 22 2021