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A355628 a(n) is the number of positive integers p that can be written as p = Product_{i = 1..n} (3 + 1/t_i) with integers t_i >= 2.

%I A355628 #14 Dec 10 2023 09:28:04
%S A355628 0,2,7,25,96,364,1344,4921
%N A355628 a(n) is the number of positive integers p that can be written as p = Product_{i = 1..n} (3 + 1/t_i) with integers t_i >= 2.
%e A355628 a(1) = 0 because (3 + 1/t_1) is not integer for t_1 >= 2.
%e A355628 a(2) = 2 because 10 = (3 + 1/4) * (3 + 1/13) and 11 = (3 + 1/2) * (3 + 1/7) and no other positive integer p can be written as p = (3 + 1/t_1) * (3 + 1/t_2) with integers t_1, t_2 >= 2, cf. A355626.
%o A355628 (PARI) See A355626.
%Y A355628 Cf. A355626, A355627, A355629, A355630, A355631.
%K A355628 hard,more,nonn
%O A355628 1,2
%A A355628 _Markus Sigg_, Jul 15 2022