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A177338 Triangle read by rows: T(n,k) = 2^(n-tau(k)) mod n, where tau(.) is the number of divisors of its argument.

%I A177338 #15 Jun 28 2024 20:50:17
%S A177338 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 A177338 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 A177338 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 A177338 Triangle read by rows: T(n,k) = 2^(n-tau(k)) mod n, where tau(.) is the number of divisors of its argument.
%e A177338 Triangle begins in row n=1 with columns 1 <= k <= n:
%e A177338   0;
%e A177338   0, 1;
%e A177338   1, 2, 2;
%e A177338   0, 0, 0, 2;
%e A177338   1, 3, 3, 4, 3;
%e A177338   2, 4, 4, 2, 4, 4;
%o A177338 (PARI) trg(nn) = {for (n= 1, nn, for (k = 1, n, print1(2^(n - numdiv(k)) % n, ", ");); print(););} \\ _Michel Marcus_, Sep 11 2013
%Y A177338 Cf. A000005, A000079, A062173, A154234, A174875.
%K A177338 nonn,tabl
%O A177338 1,5
%A A177338 _Juri-Stepan Gerasimov_, Dec 10 2010