A126571 - OEIS

%I #14 Oct 30 2019 17:41:04

%S 1,2,3,3,5,4,4,7,5,7,5,9,7,9,6,6,11,8,11,7,17,7,13,10,13,8,19,8,8,15,

%T 11,15,9,23,9,15,9,17,13,17,11,25,10,17,13,10,19,14,19,12,29,11,19,14,

%U 23,11,21,16,21,13,31,12,21,16,27,12,12,23,17,23,14,35,13,23,17,29,13,35

%N Triangle where the m-th term in row n is the n-th integer from among those positive integers coprime to m.

%H Michael De Vlieger, <a href="/A126571/b126571.txt">Table of n, a(n) for n = 1..11325</a> (rows 1 <= n <= 150).

%e The fifth positive integer coprime to 1 is 5. The fifth positive integer coprime to 2 is 9. The fifth positive integer coprime to 3 is 7. The fifth positive integer coprime to 4 is 9. And the fifth positive integer coprime to 5 is 6. So row 5 of the triangle is (5,9,7,9,6).

%e From _Michael De Vlieger_, Aug 21 2017: (Start)

%e Triangle begins:

%e    1

%e    2    3

%e    3    5    4

%e    4    7    5    7

%e    5    9    7    9    6

%e    6   11    8   11    7   17

%e    7   13   10   13    8   19    8

%e    8   15   11   15    9   23    9   15

%e    9   17   13   17   11   25   10   17   13

%e   10   19   14   19   12   29   11   19   14   23

%e   11   21   16   21   13   31   12   21   16   27   12

%e   12   23   17   23   14   35   13   23   17   29   13   35

%e (End)

%t f[m_, n_] := Block[{k = 0, c = n},While[c > 0,k++;While[GCD[k, m] > 1, k++ ];c--;];k];Flatten@Table[f[m, n], {n, 12}, {m, n}] (* _Ray Chandler_, Dec 29 2006 *)

%Y Cf. A126572, A077581.

%K nonn,tabl

%O 1,2

%A _Leroy Quet_, Dec 28 2006

%E Extended by _Ray Chandler_, Dec 29 2006