A228147 Triangle T(n,k), read by rows: T(n,k) is the denominator of (1+2^(n-k+1))/(1-2^(k+1)).
1, 1, 1, 1, 3, 7, 1, 1, 7, 5, 1, 3, 7, 3, 31, 1, 1, 7, 5, 31, 21, 1, 3, 7, 15, 31, 63, 127, 1, 1, 7, 5, 31, 7, 127, 85, 1, 3, 7, 3, 31, 63, 127, 51, 511, 1, 1, 7, 5, 31, 21, 127, 85, 511, 341, 1, 3, 7, 15, 31, 63, 127, 15, 511, 1023, 2047, 1, 1, 7, 5, 31
Offset: 0
Examples
Triangle begins: 1; 1,1; 1,3,7; 1,1,7,5; 1,3,7,3,31; 1,1,7,5,31,21; 1,3,7,15,31,63,127; 1,1,7,5,31,7,127,85; 1,3,7,3,31,63,127,51,511; 1,1,7,5,31,21,127,85,511,341; 1,3,7,15,31,63,127,15,511,1023,2047; 1,1,7,5,31,21,127,85,511,341,2047,1365; etc.
Links
- Vincenzo Librandi, Rows n = 0..100, flattened
Programs
-
Magma
[Denominator((1+2^(n-k+1))/(1-2^(k+1))): k in [0..n], n in [0..11]];
-
Mathematica
a[n_, k_] := Denominator[(1 + 2^(n - k + 1))/(1 - 2^(k + 1))]; Table[a[n, k], {n, 0, 11}, {k, 0, n}] // Flatten
Comments