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A174428
Triangle read by rows: R(n,k)= sigma(n) mod k, where sigma(.) is the sum of divisors.
2
0, 0, 1, 0, 0, 1, 0, 1, 1, 3, 0, 0, 0, 2, 1, 0, 0, 0, 0, 2, 0, 0, 0, 2, 0, 3, 2, 1, 0, 1, 0, 3, 0, 3, 1, 7, 0, 1, 1, 1, 3, 1, 6, 5, 4, 0, 0, 0, 2, 3, 0, 4, 2, 0, 8, 0, 0, 0, 0, 2, 0, 5, 4, 3, 2, 1, 0, 0, 1, 0, 3, 4, 0, 4, 1, 8, 6, 4, 0, 0, 2, 2, 4, 2, 0, 6, 5, 4, 3, 2, 1, 0, 0, 0, 0, 4, 0, 3, 0, 6, 4, 2, 0, 11, 10
OFFSET
1,10
EXAMPLE
The triangle starts in row n=1 with columns 1<=k<=n as:
0;
0,1;
0,0,1;
0,1,1,3;
0,0,0,2,1;
0,0,0,0,2,0;
0,0,2,0,3,2,1;
MATHEMATICA
Flatten[Table[Mod[DivisorSigma[1, n], k], {n, 20}, {k, n}]] (* Harvey P. Dale, Apr 17 2014 *)
CROSSREFS
Sequence in context: A081130 A358623 A360224 * A308347 A090225 A206705
KEYWORD
nonn,tabl
AUTHOR
STATUS
approved