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 A082817 Triangle (with distinct entries) read by rows in which row n contains n numbers whose product == -1 (mod n). 5

%I

%S 1,3,5,2,4,7,9,11,13,17,6,8,12,14,16,19,23,25,29,31,35,10,15,18,20,22,

%T 24,36,21,27,33,37,39,41,43,49,26,28,32,34,38,40,44,46,53,47,51,57,59,

%U 61,63,67,69,71,81,30,42,45,48,50,52,54,56,58,60,65,55,73,77,79,83,85

%N Triangle (with distinct entries) read by rows in which row n contains n numbers whose product == -1 (mod n).

%C Obviously all members of the n-th group are coprime to n.

%e 1

%e 3 5

%e 2 4 7

%e 9 11 13 17

%e 6 8 12 14 16

%e ...

%o (PARI) used = vector(1000); print(1); for (n = 2, 15, rowProd = 1; x = 2; for (k = 1, n - 1, while (used[x] || gcd(x, n) > 1, x = x + 1); print1(x); print1(" "); used[x] = 1; rowProd = rowProd*x; x = x + 1); while (used[x] || rowProd*x%n != n - 1, x = x + 1); print(x); used[x] = 1);

%Y Cf. A082818, A082819, A082820, A082821.

%K nonn,tabl

%O 1,2

%A _Amarnath Murthy_, Apr 22 2003

%E More terms from _David Wasserman_, Oct 05 2004

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Last modified July 25 22:19 EDT 2021. Contains 346294 sequences. (Running on oeis4.)