A049627 Array T read by diagonals; T(i,j)=(i+1)*(j+1)-H(i,j), where H is the array in A049615; thus T(i,j) is the number of lattice points in rectangle having diagonal (0,0)-to-(i,j) that are visible from (i,j).

1, 2, 2, 2, 4, 2, 2, 5, 5, 2, 2, 6, 6, 6, 2, 2, 7, 8, 8, 7, 2, 2, 8, 9, 10, 9, 8, 2, 2, 9, 11, 12, 12, 11, 9, 2, 2, 10, 12, 15, 14, 15, 12, 10, 2, 2, 11, 14, 16, 18, 18, 16, 14, 11, 2, 2, 12, 15, 19, 19, 22, 19, 19, 15, 12, 2, 2, 13, 17, 21, 23, 24, 24, 23, 21

Offset: 0

Author

Clark Kimberling

Keywords

• nonn
• tabl

Examples

			Diagonals (each starting on row 0):
  {1};
  {2,2};
  {2,4,2};
  ...
Array begins:
  1  2  2  2  2  2  2
  2  4  5  6  7  8  9
  2  5  6  8  9 11 12
  2  6  8 10 12 15 16
  2  7  9 12 14 18 19
  2  8 11 15 18 22 24
  2  9 12 16 19 24 26
		

Crossrefs

Cf. A049615.

Programs

PARI

T(n,k) = (n+1)*(k+1) - sum(i=0, n, sum(j=0, k, gcd(i,j)>1));
matrix(7,7,n,k, T(n-1,k-1)) \\ Michel Marcus, Aug 06 2021