|
|
A178478
|
|
Permutations of 12345678: Numbers having each of the decimal digits 1..8 exactly once, and no other digit.
|
|
4
|
|
|
12345678, 12345687, 12345768, 12345786, 12345867, 12345876, 12346578, 12346587, 12346758, 12346785, 12346857, 12346875, 12347568, 12347586, 12347658, 12347685, 12347856, 12347865, 12348567, 12348576, 12348657, 12348675, 12348756, 12348765
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
It would be nice to have a simple explicit formula for the n-th term.
An efficient procedure for generating the n-th term of this sequence can be found at A178475. - Nathaniel Johnston, May 19 2011
|
|
LINKS
|
|
|
MATHEMATICA
|
Take[FromDigits/@Permutations[Range[8]], 40] (* Harvey P. Dale, Oct 29 2014 *)
|
|
PROG
|
(PARI) is_A178478(x)= { vecsort(Vec(Str(x)))==Vec("12345678") }
(PARI) A178478(n)={my(b=vector(7, k, 1+(n-1)%(k+1)!\k!), t=b[7], d=vector(7, i, i+(i>=t))); for(i=1, 6, t=10*t+d[b[7-i]]; d=vecextract(d, Str("^"b[7-i]))); t*10+d[1]} \\ - M. F. Hasler (following N. Johnston's comment), Jan 10 2012
|
|
CROSSREFS
|
|
|
KEYWORD
|
fini,nonn,easy,base
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|