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

0,2

Links

Table of n, a(n) for n=0..74.

Example

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

Prog

(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

Crossrefs

Cf. A049615.

Sequence in context: A329586 A255336 A292929 * A278223 A368556 A134058

Adjacent sequences: A049624 A049625 A049626 * A049628 A049629 A049630

Keyword

nonn,tabl

Author

Clark Kimberling

Status

approved