0,6

a(5)=4 because 5!=120 and {1,2,0} is at 5-th position of 6 permutations of {0,1,2}: {{0,1,2},{0,2,1},{1,0,2},{1,2,0},{2,0,1},{2,1,0}}.

a(14)=1060707 because 14!=87178291200 and {8,7,1,7,8,2,9,1,2,0,0} is at 1060707-th position of 1247400 permutations of {0,0,1,1,2,2,7,7,8,8,9}.

Do[per=Permutations[Sort[tn=IntegerDigits[n! ]]]; Print[Position[per, tn]], {n, 0, 14}]

Sequence in context: A091280 A066155 A105308 this_sequence A078426 A114413 A110758

Adjacent sequences: A116980 A116981 A116982 this_sequence A116984 A116985 A116986

more,nonn

Zak Seidov (zakseidov(AT)yahoo.com), Apr 01 2006