A049623 a(n) = T(n,n+3), array T as in A049615.

2, 3, 7, 12, 17, 22, 31, 38, 45, 56, 65, 74, 91, 100, 111, 130, 141, 154, 177, 190, 205, 230, 249, 264, 291, 312, 329, 360, 379, 396, 433, 452, 481, 518, 539, 570, 611, 636, 659, 704, 731, 756, 809, 834, 861, 914, 947, 978, 1031, 1066, 1099, 1154, 1199, 1232, 1291, 1336, 1371, 1436, 1469, 1502, 1575

Offset: 0

Author

Clark Kimberling

Keywords

• nonn

Links

• G. C. Greubel, Table of n, a(n) for n = 0..1000

Crossrefs

Cf. A049615, A049616, A049617, A049618, A049619, A049620, A049621, A049622.

Programs

Mathematica

T[n_, k_]:= Length[Select[Flatten[Table[{x, y}, {x,0,n}, {y,0,k}], 1], GCD @@ # > 1 &]]; Table[T[n, n+3], {n,0,65}] (* G. C. Greubel, Dec 16 2019 *)

Extensions

Terms a(37) onward added by G. C. Greubel, Dec 16 2019