OFFSET
1,1
COMMENTS
The array is read by downwards antidiagonals as A(1,1), A(1,2), A(2,1), A(1,3), A(2,2), A(3,1), ...
LINKS
EXAMPLE
The top left corner of the array:
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2
6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6
20, 10, 20, 10, 20, 10, 20, 10, 20, 10, 20, 10, 20, 10, 20
42, 28, 14, 28, 14, 28, 42, 14, 42, 28, 14, 28, 14, 28, 42
110, 22, 44, 22, 44, 66, 22, 66, 44, 22, 44, 66, 66, 22, 66
156, 52, 26, 52, 78, 26, 78, 52, 26, 52, 78, 78, 26, 78, 52
272, 34, 68, 102, 34, 102, 68, 34, 68, 102, 102, 34, 102, 68, 34
342, 76, 114, 38, 114, 76, 38, 76, 114, 114, 38, 114, 76, 38, 114
506, 138, 46, 138, 92, 46, 92, 138, 138, 46, 138, 92, 46, 138, 92
812, 58, 174, 116, 58, 116, 174, 174, 58, 174, 116, 58, 174, 116, 174
930, 186, 124, 62, 124, 186, 186, 62, 186, 124, 62, 186, 124, 186, 248
1332, 148, 74, 148, 222, 222, 74, 222, 148, 74, 222, 148, 222, 296, 148
1640, 82, 164, 246, 246, 82, 246, 164, 82, 246, 164, 246, 328, 164, 82
1806, 172, 258, 258, 86, 258, 172, 86, 258, 172, 258, 344, 172, 86, 172
2162, 282, 282, 94, 282, 188, 94, 282, 188, 282, 376, 188, 94, 188, 94
2756, 318, 106, 318, 212, 106, 318, 212, 318, 424, 212, 106, 212, 106, 212
...
MATHEMATICA
lim = 13; Clear[row]; row[n_] := row[n] = Take[Prime[n]*Select[Range[lim^2], GCD[#*Prime[n], Product[Prime[i], {i, n-1}]] == 1&], lim] // Differences;
A[n_, k_] := row[n][[k]]; Table[A[n-k+1, k], {n, 1, lim-1}, {k, n, 1, -1}] // Flatten (* Jean-François Alcover, Mar 08 2016, after Michael De Vlieger in A083221 *)
PROG
AUTHOR
Antti Karttunen, Apr 19 2015
STATUS
approved