a(n) = binomial(n, smallest prime factor of n).

Terms

a(0) =1a(1) =1a(2) =1a(3) =6a(4) =1a(5) =15a(6) =1a(7) =28a(8) =84a(9) =45a(10) =1a(11) =66a(12) =1a(13) =91a(14) =455a(15) =120a(16) =1a(17) =153a(18) =1a(19) =190a(20) =1330a(21) =231a(22) =1a(23) =276a(24) =53130a(25) =325a(26) =2925a(27) =378a(28) =1a(29) =435