Decimal representation of permutations of lengths 1, 2, 3, ... arranged lexicographically.

Terms

a(0) =1a(1) =12a(2) =21a(3) =123a(4) =132a(5) =213a(6) =231a(7) =312a(8) =321a(9) =1234a(10) =1243a(11) =1324a(12) =1342a(13) =1423a(14) =1432a(15) =2134a(16) =2143a(17) =2314a(18) =2341a(19) =2413a(20) =2431a(21) =3124a(22) =3142a(23) =3214a(24) =3241a(25) =3412a(26) =3421a(27) =4123a(28) =4132a(29) =4213