A066948 Triangle of prime signature of A007870(n), read by rows.

0, 1, 1, 1, 5, 1, 6, 2, 1, 13, 5, 1, 18, 7, 2, 1, 36, 11, 3, 1, 48, 20, 5, 2, 79, 28, 9, 3, 109, 42, 13, 5, 1, 170, 64, 19, 7, 1, 230, 90, 28, 11, 2, 1, 337, 127, 40, 17, 3, 1, 453, 181, 58, 24, 5, 2, 648, 247, 80, 34, 7, 3, 859, 338, 111, 48, 11, 5, 1, 1185, 465, 151, 66, 15, 7, 1