A383240 Rectangular array read by antidiagonals where row n contains the numbers of the form prime(n)*m^2, where prime(n) does not divide m.

2, 18, 3, 50, 12, 5, 98, 48, 20, 7, 162, 75, 45, 28, 11, 242, 147, 80, 63, 44, 13, 338, 192, 180, 112, 99, 52, 17, 450, 300, 245, 175, 176, 117, 68, 19, 578, 363, 320, 252, 275, 208, 153, 76, 23, 722, 507, 405, 448, 396, 325, 272, 171, 92, 29, 882, 588, 605

Offset: 1

Author

Clark Kimberling, May 04 2025

Keywords

• nonn
• tabl

Examples

			Corner:
    2  18   50   98  162  242  338   450
    3  12   48   75  147  192  300   363
    5  20   45   80  180  245  320   405
    7  28   63  112  175  252  448   567
   11  44   99  176  275  396  539   704
   13  52  117  208  325  468  637   832
   17  68  153  272  425  612  833  1088
   19  76  171  304  475  684  931  1216
		

Crossrefs

Cf. A000040, A000290, A336615.

Programs

Mathematica

c[n_] := c[n] = Select[Range[100]^2, ! IntegerQ[#/Prime[n]] &]
r[n_] := Map[Times, Prime[n]*c[n]];
t = Table[r[n], {n, 1, 12}]; TableForm[t] (* A383240 array *)
w[n_, k_] := t[[n]][[k]];
Table[w[n - k + 1, k], {n, 12}, {k, n, 1, -1}] // Flatten (* A383240 sequence *)