Sum of exponents in prime-power factorization of n!.

Terms

a(0) =0a(1) =0a(2) =1a(3) =2a(4) =4a(5) =5a(6) =7a(7) =8a(8) =11a(9) =13a(10) =15a(11) =16a(12) =19a(13) =20a(14) =22a(15) =24a(16) =28a(17) =29a(18) =32a(19) =33a(20) =36a(21) =38a(22) =40a(23) =41a(24) =45a(25) =47a(26) =49a(27) =52a(28) =55a(29) =56