A177338 - OEIS

%I #15 Jun 28 2024 20:50:17

%S 0,0,1,1,2,2,0,0,0,2,1,3,3,4,3,2,4,4,2,4,4,1,4,4,2,4,1,4,0,0,0,0,0,0,

%T 0,0,4,2,2,1,2,5,2,5,1,2,6,6,8,6,4,6,4,8,4,1,6,6,3,6,7,6,7,3,7,6,8,4,

%U 4,8,4,4,4,4,8,4,4,4,1,7,7,10,7,5,7,5,10,5,7,11,7,2,8,8,4,8,2,8

%N Triangle read by rows: T(n,k) = 2^(n-tau(k)) mod n, where tau(.) is the number of divisors of its argument.

%e Triangle begins in row n=1 with columns 1 <= k <= n:

%e   0;

%e   0, 1;

%e   1, 2, 2;

%e   0, 0, 0, 2;

%e   1, 3, 3, 4, 3;

%e   2, 4, 4, 2, 4, 4;

%o (PARI) trg(nn) = {for (n= 1, nn, for (k = 1, n, print1(2^(n - numdiv(k)) % n, ", ");); print(););} \\ _Michel Marcus_, Sep 11 2013

%Y Cf. A000005, A000079, A062173, A154234, A174875.

%K nonn,tabl

%O 1,5

%A _Juri-Stepan Gerasimov_, Dec 10 2010