Towers of Hanoi revisited
Public  08/02/14  10xp  Programming  100.0% 
In a game of Hanoi with n disks, we can consider the layout after m moves as a permutation of {1, ..., n}
For instance, with 15 disks, after 12345 moves the layout is:
corresponding to permutation : 7 8 9 10 11 12 15 1 4 5 6 13 14 2 3
The index of this permutation in lexicographic order is 563569656784
With 70 disks, what is the index of the permutation corresponding to the layout after 123456789101112131415 moves?
[My timing: < 100 ms]
For instance, with 15 disks, after 12345 moves the layout is:
 Peg1 : 7 8 9 10 11 12 15
 Peg2 : 1 4 5 6 13 14
 Peg3 : 2 3
corresponding to permutation : 7 8 9 10 11 12 15 1 4 5 6 13 14 2 3
The index of this permutation in lexicographic order is 563569656784
With 70 disks, what is the index of the permutation corresponding to the layout after 123456789101112131415 moves?
[My timing: < 100 ms]
New Members
 nebula001 2d:21h
 PeterisP 1w
 Arun_CoDeR 1w
 hankim 2w:3d
 chfmoe 3w
Fresh Problems

Kimberling Sequence 1d:2h
solved by 6 
Palindromic Infinite Sequence 1w:1d
solved by 3 
Convergents of infinite sum 1w:5d
solved by 5 
Permutation Order II 2w:1d
solved by 8 
Integral circle packings 2 2w:4d
solved by 3