A227082 a(n) is the least positive integer not yet in the sequence coprime to a(d) for every proper divisor d of n.

1, 2, 3, 5, 4, 7, 6, 9, 8, 11, 10, 13, 12, 17, 19, 23, 14, 25, 15, 21, 29, 27, 16, 31, 33, 35, 37, 41, 18, 43, 20, 47, 49, 39, 53, 59, 22, 61, 55, 67, 24, 65, 26, 71, 73, 45, 28, 79, 77, 83, 85, 89, 30, 97, 51, 91, 32, 95, 34, 101, 36, 57, 103, 107, 109, 113, 38, 121, 115, 125, 40, 127, 42, 63, 119, 131, 133, 137, 44, 139, 143, 145, 46, 149

Offset

1,2

Comments

This is a permutation of the positive integers.

The subsequence (a(prime(i))) is strictly increasing.

a(i) < a(prime(j)) implies i < prime(j).

Links

Paul Tek, Table of n, a(n) for n = 1..10000

Paul Tek, PERL program for this sequence

Example

a(1) = min { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, ... } = 1
a(2) = min {    2, 3, 4, 5, 6, 7, 8, 9, 10, 11, ... } = 2
a(3) = min {       3, 4, 5, 6, 7, 8, 9, 10, 11, ... } = 3
a(4) = min {             5,    7,    9,     11, ... } = 5
a(5) = min {          4,    6, 7, 8, 9, 10, 11, ... } = 4
a(6) = min {                   7,           11, ... } = 7

Prog

(Perl) See Tek link.

Crossrefs

Cf. A227142.

Sequence in context: A230086 A375374 A333404 * A227142 A246696 A246698

Adjacent sequences: A227079 A227080 A227081 * A227083 A227084 A227085

Keyword

nonn

Author

Paul Tek, Jun 30 2013

Status

approved