OFFSET
2,1
COMMENTS
The number of derangements of {1,2,...,n} is given in A000166.
This sequence is unsatisfactory for n >= 10. To have a sequence that is defined for all n, the derangements should be comma-separated lists, with keyword tabf. - N. J. A. Sloane, Nov 15 2018
EXAMPLE
Triangle begins:
21;
231, 312;
2143, 2341, 2413, 3142, 3412, 3421, 4123, 4312, 4321;
21453, 21534, 23154, 23451, 23514, 24153, 24513, 24531, 25134, ...
...
From David A. Corneth, Nov 15 2018: (Start)
43512 is in the sequence because no digit is equal to the index of the digit in the number (with offset 1).
43125 is not in the sequence because 5 is at the fifth position. (End)
MATHEMATICA
Needs["Combinatorica`"]; Flatten @ Table[FromDigits /@ Derangements [Table[i, {i, n}]], {n, 9}] (* For first 150504 terms, Amiram Eldar, Nov 15 2018 after Zak Seidov at A030299 *)
PROG
(Perl) use ntheory ":all"; my(@L, @d); do { @d=(1..$_); forderange { push @L, join"", @d[@_]; } $_; } for 2..6; say join ", ", @L; # Dana Jacobsen, Nov 15 2018
CROSSREFS
KEYWORD
nonn,base,tabf
AUTHOR
Enrique Navarrete, Nov 14 2018
STATUS
approved