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A305996 Rectangular array, by antidiagonals; row n consists of the numbers R(n)/n, where R(n) is row n of the array at A305995.

%I A305996 #6 Jun 17 2018 09:47:09
%S A305996 1,10,1,65,34,1,130,260,2,1,260,884,5,10,1,340,1300,10,26,10,2,1105,
%T A305996 3380,20,260,340,20,1,1972,8840,50,5140,650,52,2,1,2210,31300,65,8840,
%U A305996 1565,100,5,260,1,4420,82948,68,21320,5525,520,10,514,2,2
%N A305996 Rectangular array, by antidiagonals; row n consists of the numbers R(n)/n, where R(n) is row n of the array at A305995.
%e A305996 Northwest corner:
%e A305996   1  10   65  130   260    340   1105
%e A305996   1  34  260  884  1300   3380   8840
%e A305996   1   2    5   10    20     50     65
%e A305996   1  10   26  260  5140   8840  21430
%e A305996   1  10  340  650  1565   5525   6260
%e A305996   2  30   52  100   520  10280  17680
%e A305996   1   2    5   10    20     25     50
%t A305996 z = 3000; r[n_] := Select[Divisors[n], GCD[#, n/#] == 1 &]; k[n_] := Length[r[n]];
%t A305996 t[n_] := Table[r[n][[k[n] + 1 - i]]/r[n][[k[1] + i - 1]], {i, 1, k[n]}];
%t A305996 s = Table[Plus @@ t[n], {n, 1, z}];
%t A305996 a[n_] := If[IntegerQ[s[[n]]], 1, 0];
%t A305996 u = Table[a[n], {n, 1, z}]; (*A229996*)
%t A305996 d = Denominator[s]; row[n_] := Flatten[Position[d, n]] (*A305995 array*)
%t A305996 rr[n_] := row[n]/n;
%t A305996 TableForm[Table[rr[n], {n, 1, 100}]] (* A305996 array *)
%t A305996 r1[n_, k_] := rr[n][[k]];
%t A305996 Flatten[Table[r1[n - k + 1, k], {n, 5}, {k, n, 1, -1}]]  (* A305996 sequence *)
%Y A305996 Cf. A077610, A229994, A229996, A229997, A229998, A229998, A305995.
%K A305996 nonn,tabl
%O A305996 1,2
%A A305996 _Clark Kimberling_, Jun 16 2018