A174875 - OEIS

%I #16 Jun 29 2024 09:09:34

%S 0,0,1,0,0,0,0,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,0,0,0,0,1,1,0,1,3,

%T 1,3,0,1,1,1,1,1,1,1,1,0,0,0,0,0,2,0,2,0,2,0,0,0,0,0,0,0,0,0,0,0,0,0,

%U 0,1,0,0,0,0,1,0,0,4,0,0,0,2,0,2,0,2,2,2,0,2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0

%N Triangle read by rows: T(n,k) = sigma(n) mod tau(k), where sigma(.) is the sum of divisors and tau(.) is the number of divisors.

%e The triangle starts at row n=1 with columns k = 1..n:

%e   0;

%e   0,1;

%e   0,0,0;

%e   0,1,1,1;

%e   0,0,0,0,0;

%e   0,0,0,0,0,0;

%e   0,0,0,2,0,0,0;

%e   0,1,1,0,1,3,1,3;

%e   0,1,1,1,1,1,1,1,1;

%e   0,0,0,0,0,2,0,2,0,2;

%e   0,0,0,0,0,0,0,0,0,0,0;

%t Array[Mod[DivisorSigma[1, #], DivisorSigma[0, Range[#]]] &, 15] (* _Paolo Xausa_, Jun 28 2024 *)

%Y Cf. A000005, A000203, A054025 (right diagonal).

%K nonn,tabl,easy

%O 1,25

%A _Juri-Stepan Gerasimov_, Dec 02 2010