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

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, 24, 36, 21, 27, 33, 37, 39, 41, 43, 49, 26, 28, 32, 34, 38, 40, 44, 46, 53, 47, 51, 57, 59, 61, 63, 67, 69, 71, 81, 30, 42, 45, 48, 50, 52, 54, 56, 58, 60, 65, 55, 73, 77, 79, 83, 85

Offset

1,2

Comments

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

Links

Table of n, a(n) for n=1..72.

Example

1
3 5
2 4 7
9 11 13 17
6 8 12 14 16
...

Prog

(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);

Crossrefs

Cf. A082818, A082819, A082820, A082821.

Sequence in context: A219249 A203553 A081964 * A084753 A163364 A336760

Adjacent sequences: A082814 A082815 A082816 * A082818 A082819 A082820

Keyword

nonn,tabl

Author

Amarnath Murthy, Apr 22 2003

Extensions

More terms from David Wasserman, Oct 05 2004

Status

approved