Product of the nonzero exponents in the prime factorization of n!.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =3a(5) =3a(6) =8a(7) =8a(8) =14a(9) =28a(10) =64a(11) =64a(12) =100a(13) =100a(14) =220a(15) =396a(16) =540a(17) =540a(18) =768a(19) =768a(20) =1152a(21) =1944a(22) =4104a(23) =4104a(24) =5280a(25) =7920a(26) =16560a(27) =21528a(28) =31200a(29) =31200