cp's OEIS Frontend

A147861 Triangle read by rows: T(n,k)=min(k, n/k) if k divides n, T(n,k)=0 otherwise (n >=1, 1<=k<=n).

%I A147861 #7 Mar 11 2014 01:34:13
%S A147861 1,1,1,1,0,1,1,2,0,1,1,0,0,0,1,1,2,2,0,0,1,1,0,0,0,0,0,1,1,2,0,2,0,0,
%T A147861 0,1,1,0,3,0,0,0,0,0,1,1,2,0,0,2,0,0,0,0,1,1,0,0,0,0,0,0,0,0,0,1,1,2,
%U A147861 3,3,0,2,0,0,0,0,0,1,1,0,0,0,0,0,0,0,0,0,0,0,1
%N A147861 Triangle read by rows: T(n,k)=min(k, n/k) if k divides n, T(n,k)=0 otherwise (n >=1, 1<=k<=n).
%H A147861 Omar E. Pol, <a href="http://www.polprimos.com">Determinacion geometrica de los numeros primos y perfectos</a> [From _Omar E. Pol_, Jul 20 2009]
%H A147861 Omar E. Pol, <a href="http://www.polprimos.com/imagenespub/polprdipi.jpg">Illustration: Divisors and pi(x)</a> [From _Omar E. Pol_, Jul 20 2009]
%e A147861 Triangle begins:
%e A147861 1;
%e A147861 1,1;
%e A147861 1,0,1;
%e A147861 1,2,0,1;
%e A147861 1,0,0,0,1;
%e A147861 1,2,2,0,0,1;
%e A147861 1,0,0,0,0,0,1;
%e A147861 1,2,0,2,0,0,0,1;
%e A147861 1,0,3,0,0,0,0,0,1;
%e A147861 1,2,0,0,2,0,0,0,0,1;
%e A147861 1,0,0,0,0,0,0,0,0,0,1;
%e A147861 1,2,3,3,0,2,0,0,0,0,0,1;
%e A147861 1,0,0,0,0,0,0,0,0,0,0,0,1;
%e A147861 1,2,0,0,0,0,2,0,0,0,0,0,0,1;
%e A147861 1,0,3,0,3,0,0,0,0,0,0,0,0,0,1;
%e A147861 1,2,0,4,0,0,0,2,0,0,0,0,0,0,0,1;
%e A147861 1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1;
%e A147861 1,2,3,0,0,3,0,0,2,0,0,0,0,0,0,0,0,1;
%e A147861 1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1;
%e A147861 1,2,0,4,4,0,0,0,0,2,0,0,0,0,0,0,0,0,0,1;
%e A147861 1,0,3,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,1;
%e A147861 1,2,0,0,0,0,0,0,0,0,2,0,0,0,0,0,0,0,0,0,0,1;
%e A147861 1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1;
%e A147861 1,2,3,4,0,4,0,3,0,0,0,2,0,0,0,0,0,0,0,0,0,0,0,1;
%e A147861 1,0,0,0,5,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1;
%e A147861 1,2,0,0,0,0,0,0,0,0,0,0,2,0,0,0,0,0,0,0,0,0,0,0,0,1;
%e A147861 1,0,3,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1;
%e A147861 1,2,0,4,0,0,4,0,0,0,0,0,0,2,0,0,0,0,0,0,0,0,0,0,0,0,0,1;
%e A147861 1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1;
%e A147861 1,2,3,0,5,5,0,0,0,3,0,0,0,0,2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1;
%e A147861 ...
%e A147861 Row sums: A117004.
%Y A147861 Cf. A000005, A008578, A027750, A051731, A117004, A127093, A161345, A161424, A161835, A162526, A162527, A162528, A162529, A162530, A162531, A162532. [From _Omar E. Pol_, Jul 20 2009]
%K A147861 nonn,tabl
%O A147861 1,8
%A A147861 _Omar E. Pol_, Nov 16 2008, Jul 20 2009
%E A147861 Submitted without a definition, which was supplied by _Jon E. Schoenfield_, Dec 13 2008