OFFSET
1,2
EXAMPLE
The corner of the square array begins:
1, 3, 4, 7, 6, 12, 8, 15, 13, 18...
2, 6, 8, 14, 12, 24, 16, 30, 26, 36...
3, 9, 12, 21, 18, 36, 24, 45, 39, 54...
5, 15, 20, 35, 30, 60, 40, 75, 65, 90...
7, 21, 28, 49, 42, 84, 56, 105, 91, 126...
11, 33, 44, 77, 66, 132, 88, 165, 143, 198...
13, 39, 52, 91, 78, 156, 104, 195, 169, 234...
17, 51, 68, 119, 102, 204, 136, 255, 221, 306...
19, 57, 76, 133, 114, 228, 152, 285, 247, 342...
23, 69, 92, 161, 138, 276, 184, 345, 299, 414...
...
MATHEMATICA
Table[If[# == 1, 1, Prime[# - 1]] DivisorSigma[1, k] &@(n - k + 1), {n, 12}, {k, n}] // Flatten (* Michael De Vlieger, Apr 28 2016 *)
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Omar E. Pol, Apr 28 2016
STATUS
approved