Some permutation of digits is a factorial number.

Terms

a(0) =1a(1) =2a(2) =6a(3) =10a(4) =20a(5) =24a(6) =42a(7) =60a(8) =100a(9) =102a(10) =120a(11) =200a(12) =201a(13) =204a(14) =207a(15) =210a(16) =240a(17) =270a(18) =402a(19) =420a(20) =600a(21) =702a(22) =720a(23) =1000a(24) =1002a(25) =1020a(26) =1200a(27) =2000a(28) =2001a(29) =2004