A023226 Numbers n such that n and 7n + 8 both prime.

3, 5, 17, 29, 47, 53, 59, 89, 107, 137, 149, 227, 347, 359, 383, 389, 443, 479, 503, 509, 557, 593, 599, 617, 659, 683, 743, 773, 839, 857, 887, 947, 953, 1049, 1097, 1187, 1217, 1259, 1307, 1319, 1373, 1409, 1433, 1493, 1499, 1607, 1613, 1637, 1667, 1697, 1709