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

Author

Juri-Stepan Gerasimov, Nov 28 2010

Keywords

• nonn
• tabl

Examples

			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;
		

Crossrefs

Cf. A000203, A154234.

Programs

Mathematica

Flatten[Table[Mod[DivisorSigma[1,n],k],{n,20},{k,n}]] (* Harvey P. Dale, Apr 17 2014 *)