A049621 a(n) = T(n,n+1), array T as in A049615.

0, 1, 4, 8, 12, 18, 24, 30, 38, 48, 56, 66, 76, 86, 102, 118, 128, 142, 156, 170, 192, 214, 228, 246, 268, 288, 312, 338, 356, 380, 404, 422, 452, 484, 514, 550, 576, 598, 634, 674, 700, 732, 764, 790, 836, 882, 908, 942, 982, 1020, 1070, 1118, 1148, 1186, 1238, 1286, 1340, 1392, 1424, 1470, 1516

Offset

0,3

Links

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

Mathematica

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

Crossrefs

Cf. A049615, A049616, A049617, A049618, A049619, A049620, A049622, A049623.

Sequence in context: A311633 A311634 A311635 * A072511 A156324 A311636

Adjacent sequences: A049618 A049619 A049620 * A049622 A049623 A049624

Keyword

nonn

Author

Clark Kimberling

Extensions

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

Status

approved