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a(n) = T(n,n+3), array T as in A049615.
4

%I #9 Dec 16 2019 22:10:10

%S 2,3,7,12,17,22,31,38,45,56,65,74,91,100,111,130,141,154,177,190,205,

%T 230,249,264,291,312,329,360,379,396,433,452,481,518,539,570,611,636,

%U 659,704,731,756,809,834,861,914,947,978,1031,1066,1099,1154,1199,1232,1291,1336,1371,1436,1469,1502,1575

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

%H G. C. Greubel, <a href="/A049623/b049623.txt">Table of n, a(n) for n = 0..1000</a>

%t 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 *)

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

%K nonn

%O 0,1

%A _Clark Kimberling_

%E Terms a(37) onward added by _G. C. Greubel_, Dec 16 2019