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

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, 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, 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

Offset: 1

Author

Juri-Stepan Gerasimov, Dec 10 2010

Keywords

• nonn
• tabl

Examples

			Triangle begins in row n=1 with columns 1 <= k <= n:
  0;
  0, 1;
  1, 2, 2;
  0, 0, 0, 2;
  1, 3, 3, 4, 3;
  2, 4, 4, 2, 4, 4;
		

Crossrefs

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

Programs

PARI

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