A277427 Prime permutations, ordered lexicographically.

1, 2, 1, 3, 1, 2, 3, 2, 1, 4, 1, 2, 3, 4, 1, 3, 2, 4, 2, 1, 3, 4, 2, 3, 1, 4, 3, 1, 2, 4, 3, 2, 1, 5, 1, 2, 3, 4, 5, 1, 2, 4, 3, 5, 1, 3, 2, 4, 5, 1, 3, 4, 2, 5, 1, 4, 2, 3, 5, 1, 4, 3, 2, 5, 2, 1, 3, 4, 5, 2, 1, 4, 3, 5, 2, 3, 1, 4, 5, 2, 3, 4, 1, 5, 2, 4, 1, 3, 5, 2, 4, 3, 1, 5, 3, 1, 2, 4, 5, 3, 1, 4, 2, 5, 3, 2, 1

Offset: 1

Author

Gus Wiseman, Oct 14 2016

Keywords

• nonn
• tabf

Comments

A permutation of {1..n} is prime (in the sense of A215474) iff it is of the form (n, q_1, q_2, ..., q_{n-1}).

Row n in the triangle consists of all permutations consisting of n followed by a permutation of 1..n-1, in lexicographic order.

Examples

			The sequence of prime permutations begins:
1,
21,
312, 321,
4123, 4132, 4213, 4231, 4312, 4321,
...
		

Links

• Gus Wiseman, Table of n, a(n) for n = 1..5912

Crossrefs

Cf. A215474, A254040, A060223, A005117.

Programs

Maple

seq(op(map(t -> (n,op(t)), combinat:-permute(n-1))), n=1..6); # Robert Israel, Nov 07 2016

Mathematica

row[n_] := Join[{n}, #]& /@ Permutations[Range[n-1]];
Array[row, 5] // Flatten (* Jean-François Alcover, Apr 10 2019 *)