

A121998


Table, nth row gives numbers between 1 and n that have a common factor with n.


9



2, 3, 2, 4, 5, 2, 3, 4, 6, 7, 2, 4, 6, 8, 3, 6, 9, 2, 4, 5, 6, 8, 10, 11, 2, 3, 4, 6, 8, 9, 10, 12, 13, 2, 4, 6, 7, 8, 10, 12, 14, 3, 5, 6, 9, 10, 12, 15, 2, 4, 6, 8, 10, 12, 14, 16, 17, 2, 3, 4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 19, 2, 4, 5, 6, 8, 10, 12, 14, 15, 16, 18, 20, 3, 6, 7, 9, 12, 14, 15
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OFFSET

2,1


COMMENTS

Row n contains numbers m <= n such that gcd(m,n) > 1, i.e., numbers m in the cototient of n.  Michael De Vlieger, Mar 13 2018


LINKS

Michael De Vlieger, Table of n, a(n) for n = 2..12949 (rows 2 <= n <= 256).


EXAMPLE

2;
3;
2,4;
5;
2,3,4,6;
7;
...


MATHEMATICA

Table[Select[Range@ n, ! CoprimeQ[#, n] &], {n, 20}] // Flatten (* Michael De Vlieger, Mar 13 2018 *)


CROSSREFS

Cf. A051953 (row lengths), A038566, A081520, A133995 (nondivisors in the cototient of n).
Sequence in context: A326764 A071495 A071515 * A120499 A027749 A226208
Adjacent sequences: A121995 A121996 A121997 * A121999 A122000 A122001


KEYWORD

nonn,tabf


AUTHOR

Franklin T. AdamsWatters, Sep 11 2006


STATUS

approved



