A225529 Number of distinct products i*j over all pairs (i,j) with i,j >= 0 and i+j <= n and gcd(i,j) <= 1.

1, 1, 2, 3, 4, 6, 7, 9, 11, 14, 16, 20, 22, 26, 29, 32, 35, 41, 44, 50, 54, 59, 63, 70, 74, 80, 85, 92, 98, 108, 112, 121, 129, 137, 144, 153, 158, 170, 177, 186, 192, 204, 210, 222, 231, 240, 249, 262, 270, 284, 293, 305, 315, 331, 340, 353

Offset

0,3

Comments

Note that gcd(0,m) = m for any m.

Links

Robert Price, Table of n, a(n) for n = 0..400

Mathematica

f[n_]:=Length[Complement[Union[Flatten[Table[If[i+j≤n&&GCD[i, j]<=1, {i*j}], {i, 0, n}, {j, 0, n}], 1]], {Null}]]; Table[f[n], {n, 0, 100}]

Crossrefs

Cf. A018805, A027430, A100448, A100449, A100450, A213207, A213208.

Sequence in context: A047872 A173254 A015851 * A065156 A097987 A049149

Adjacent sequences: A225526 A225527 A225528 * A225530 A225531 A225532

Keyword

nonn,easy

Author

Robert Price, May 09 2013

Status

approved