

A119018


a(1) = 0; a(n) is the smallest number not yet used that is not relatively prime to n nor relatively prime to a(n1).


4



0, 2, 6, 4, 10, 8, 14, 12, 3, 15, 33, 9, 39, 18, 20, 16, 34, 22, 38, 24, 21, 28, 46, 26, 30, 32, 36, 40, 58, 42, 62, 44, 11, 66, 45, 27, 111, 48, 51, 54, 82, 50, 86, 52, 60, 56, 94, 64, 70, 5, 75, 65, 265, 80, 25, 35, 63, 72, 118, 68, 122, 74, 78, 76, 90, 55, 335, 85, 102, 84, 142
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OFFSET

1,2


COMMENTS

Conjecture: this sequence includes every integer greater than 1.


LINKS

Ivan Neretin, Table of n, a(n) for n = 1..2000


EXAMPLE

a(12) must have a common factor with 12 and a(11) = 33. The first few such values are 3, 6 and 9; 3 and 6 have already been used, so a(12)=9.


MAPLE

A119018 := proc(nmin) local a, anxt ; a := [0] ; while nops(a) < nmin do anxt := 1 ; n := nops(a)+1 ; while anxt in a or gcd(n, anxt) = 1 or gcd(op(1, a), anxt) = 1 do anxt := anxt+1 ; od ; a := [op(a), anxt]; od: RETURN(a) ; end: A119018(100) ; # R. J. Mathar, Sep 07 2007


MATHEMATICA

a = {0}; Do[k = 1; While[MemberQ[a, k]  GCD[k, n] == 1  GCD[k, a[[1]]] == 1, k++]; AppendTo[a, k], {n, 2, 71}]; a (* Ivan Neretin, Jul 09 2015 *)


CROSSREFS

Cf. A119019.
Sequence in context: A066678 A306645 A113571 * A264647 A094748 A245579
Adjacent sequences: A119015 A119016 A119017 * A119019 A119020 A119021


KEYWORD

nonn


AUTHOR

Franklin T. AdamsWatters, May 08 2006


EXTENSIONS

Definition corrected by R. J. Mathar, Sep 07 2007


STATUS

approved



