A174428 Triangle read by rows: R(n,k)= sigma(n) mod k, where sigma(.) is the sum of divisors.

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

Links

Table of n, a(n) for n=1..105.

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

Cf. A000203, A154234.

Sequence in context: A081130 A358623 A360224 * A308347 A090225 A206705

Adjacent sequences: A174425 A174426 A174427 * A174429 A174430 A174431

Keyword

nonn,tabl

Author

Juri-Stepan Gerasimov, Nov 28 2010

Status

approved