A143470 Triangle read by rows, A000012 * A143316, 1 <= k <= n.
1, 3, 1, 7, 1, 1, 11, 3, 1, 1, 19, 3, 1, 1, 1, 23, 7, 3, 1, 1, 1, 35, 7, 3, 1, 1, 1, 1, 43, 11, 3, 3, 1, 1, 1, 1, 55, 11, 7, 3, 1, 1, 1, 1, 1, 63, 19, 7, 3, 3, 1, 1, 1, 1, 1, 83, 19, 7, 3, 3, 1, 1, 1, 1, 1, 1, 91, 23, 11, 7, 3, 3, 1, 1, 1, 1, 1, 1, 115, 23, 11, 7, 3, 3, 1, 1, 1, 1, 1, 1, 1
Offset: 1
Keywords
Examples
First few rows of the triangle: 1; 3, 1; 7, 1, 1; 11, 3, 1, 1; 19, 3, 1, 1, 1; 23, 7, 3, 1, 1, 1; 35, 7, 3, 1, 1, 1, 1; ...
Formula
Extensions
a(28) = 1 inserted by Georg Fischer, Aug 18 2023
Comments