Denominator of Product_{i=1..n} (p_i+1)/(p_i-1). Numerators are in A078559.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =5a(5) =5a(6) =10a(7) =1a(8) =11a(9) =11a(10) =11a(11) =11a(12) =55a(13) =5a(14) =115a(15) =1495a(16) =8671a(17) =43355a(18) =476905a(19) =16691675a(20) =16691675a(21) =43398355a(22) =254190365a(23) =559218803a(24) =559218803a(25) =13980470075a(26) =1075420775a(27) =56997301075a(28) =1036314565a(29) =1036314565