cp's OEIS Frontend

A249327 Rectangular array T(n,k) = f(n)*k^2, where f = A005117 (squarefree numbers); n, k >= 1; read by antidiagonals.

%I A249327 #15 Oct 31 2014 22:26:53
%S A249327 1,4,2,9,8,3,16,18,12,5,25,32,27,20,6,36,50,48,45,24,7,49,72,75,80,54,
%T A249327 28,10,64,98,108,125,96,63,40,11,81,128,147,180,150,112,90,44,13,100,
%U A249327 162,192,245,216,175,160,99,52,14,121,200,243,320,294,252,250
%N A249327 Rectangular array T(n,k) = f(n)*k^2, where f = A005117 (squarefree numbers); n, k >= 1; read by antidiagonals.
%C A249327 Every positive integer occurs exactly once.
%F A249327 T(1,k) = A000290(k), T(2,k) = A001105(k), T(3,k) = A033428(k), T(4,k) = A033429(k), T(5,.) through T(10,.) are A033581, A033582, A033583, A033584, A152742 and A144555 without initial 0. - _M. F. Hasler_, Oct 31 2014
%e A249327 Northwest corner:
%e A249327 1   4    9    16   25    36    49
%e A249327 2   8    18   32   50    72    98
%e A249327 3   12   27   48   75    108   147
%e A249327 5   20   45   80   125   180   245
%e A249327 6   24   54   96   150   216   294
%t A249327 z = 20; f = Select[Range[10000], SquareFreeQ[#] &];
%t A249327 u[n_, k_] := f[[n]]*k^2; t = Table[u[n, k], {n, 1, 20}, {k, 1, 20}];
%t A249327 TableForm[t] (* A249327 array *)
%t A249327 Table[u[k, n - k + 1], {n, 1, 15}, {k, 1, n}] // Flatten (* A249327 sequence *)
%Y A249327 Cf. A005117, A000037 (is partitioned by the rows of A249327, excluding the first).
%K A249327 nonn,tabl,easy
%O A249327 1,2
%A A249327 _Clark Kimberling_, Oct 26 2014