A114861 a(n) is smallest positive integer not among the earlier terms of the sequence, not equal to n and which is coprime to its adjacent terms in the sequence.

2, 1, 4, 3, 7, 5, 6, 11, 8, 9, 10, 13, 12, 17, 14, 15, 16, 19, 18, 23, 20, 21, 22, 25, 24, 29, 26, 27, 28, 31, 30, 37, 32, 33, 34, 35, 36, 41, 38, 39, 40, 43, 42, 47, 44, 45, 46, 49, 48, 53, 50, 51, 52, 55, 54, 59, 56, 57, 58, 61, 60, 67, 62, 63, 64, 65, 66, 71, 68, 69, 70, 73

Offset

1,1

Comments

Sequence is a permutation of the positive integers. (Inverse permutation is sequence A114862.)

Links

Table of n, a(n) for n=1..72.

Example

a(8) = 11 since 11 is the smallest positive integer not among the first 7 terms of the sequence, not equal to 8 and which is coprime to a(7) = 6.

Mathematica

f[l_] := Block[{k = 1}, While[k == Length[l] + 1 || MemberQ[l, k] || GCD[k, Last[l]] > 1, k++ ]; Return[Append[l, k]]; ]; Nest[f, {}, 76] (* Ray Chandler, Jan 02 2006 *)

Crossrefs

Cf. A114862.

Sequence in context: A281853 A077912 A077963 * A086512 A120751 A054082

Adjacent sequences: A114858 A114859 A114860 * A114862 A114863 A114864

Keyword

nonn

Author

Leroy Quet, Jan 02 2006

Extensions

More terms from Ray Chandler and Klaus Brockhaus, Jan 02 2006

Status

approved