The next number in the series 2, 5, 14, 41 is

Each term is three times the previous term minus 1: 2 × 3 − 1 = 5, 5 × 3 − 1 = 14 and 14 × 3 − 1 = 41. So the next term is 41 × 3 − 1 = 122; 123 would be the product without subtracting 1.