OFFSET
1,2
COMMENTS
FORMULA
T(n,k) = -I(gcd(n,k) = 1) + 2 * Sum_{d|gcd(n,k)} d * mu(n/d) for n >= 1 and 1 <= k <= n, where I(condition) = 1 if the condition holds, and 0 otherwise. - Petros Hadjicostas, Jul 29 2019
EXAMPLE
First few rows of the triangle =
1;
-3, 2;
-3, -3, 4;
-1, -4, -1, 4;
-3, -3, -3, -3, 8;
1, -2, -4, -2, 1, 4;
-3, -3, -3, -3, -3, -3, 12;
-1, 0, -1, -8 -1, 0, -1, 8;
-1, -1, -6, -1, -1, -6, -1, -1, 12;
1, -2, 1, -2, -8, -2, 1, -2, 1, 8;
-3, -3, -3, -3, -3, -3, -3, -3, -3, -3, 20;
...
CROSSREFS
KEYWORD
tabl,sign
AUTHOR
Gary W. Adamson, Sep 20 2008
STATUS
approved