OFFSET
1,1
LINKS
Seiichi Manyama, Antidiagonals n = 1..140, flattened
Wikipedia, Coprime integers
FORMULA
A(n,k) = A(k,n).
EXAMPLE
A(2,1)=12 because there are twelve coprime pairs (1,0), (2,1), (1,1), (0,1), (-1,1), (-2,1), (-1,0), (-2,-1), (-1,-1), (0,-1), (1,-1), (2,-1).
Square array begins:
8, 12, 16, 20, 24, 28, 32, ...
12, 16, 24, 28, 36, 40, 48, ...
16, 24, 32, 40, 52, 56, 68, ...
20, 28, 40, 48, 64, 68, 84, ...
24, 36, 52, 64, 80, 88, 108, ...
28, 40, 56, 68, 88, 96, 120, ...
32, 48, 68, 84, 108, 120, 144, ...
36, 52, 76, 92, 120, 132, 160, ...
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Seiichi Manyama, Nov 27 2017
STATUS
approved