A228035 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, 3, 1, 1, 7, 1, 3, 7, 15, 1, 1, 1, 5, 31, 1, 3, 7, 15, 31, 63, 1, 1, 7, 1, 31, 21, 127, 1, 3, 1, 15, 31, 9, 127, 255, 1, 1, 7, 5, 1, 21, 127, 85, 511, 1, 3, 7, 15, 31, 63, 127, 255, 511, 1023, 1, 1, 1, 1, 31, 1, 127, 17, 73, 341, 2047, 1, 3, 7, 15, 31, 63
Offset: 0
Examples
Triangle begins: 1; 1, 3; 1, 1, 7; 1, 3, 7, 15; 1, 1, 1, 5, 31; 1, 3, 7, 15, 31, 63; 1, 1, 7, 1, 31, 21, 127; 1, 3, 1, 15, 31, 9, 127, 255; 1, 1, 7, 5, 1, 21, 127, 85, 511; 1, 3, 7, 15, 31, 63, 127, 255, 511, 1023; 1, 1, 1, 1, 31, 1, 127, 17, 73, 341, 2047; 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