OFFSET
0,2
COMMENTS
Specifically, x^2 + y^2 <= i^2 + j^2.
FORMULA
T(n,0) = A000328(n).
EXAMPLE
Antidiagonals (each starting on row 0):
{1},
{5, 5},
{13, 9, 13},
...
Array begins:
1 5 13 29 49 81
5 9 21 37 57 89
13 21 25 45 69 97
29 37 45 61 81 109
49 57 69 81 101 137
81 89 97 109 137 161
PROG
(PARI) T(n, k) = my(z=norml2([n, k]), m=ceil(sqrt(2)*max(n, k))); sum(x=-m, m, sum(y=-m, m, norml2([x, y]) <= z)); \\ Michel Marcus, Aug 07 2021
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
STATUS
approved