Number of pairs (a,b) such that a*b = n! and d(a) = d(b) with d = A000005 and a <= b.

Terms

a(0) =1a(1) =1a(2) =0a(3) =1a(4) =0a(5) =1a(6) =1a(7) =1a(8) =0a(9) =5a(10) =3a(11) =5a(12) =5a(13) =13a(14) =11a(15) =11a(16) =11a(17) =13a(18) =45a(19) =105a(20) =136a(21) =105a(22) =165a(23) =332a(24) =492a(25) =501a(26) =482a(27) =684a(28) =720a(29) =1095