श्रेणी में लुप्त पद (?) ज्ञात कीजिए: 13, 14, 18, 27, ?, 68, 104 ........

The differences between terms are perfect squares: 14 − 13 = 1, 18 − 14 = 4, 27 − 18 = 9, then 16, 25, 36. So the missing term = 27 + 16 = 43 (check: 43 + 25 = 68 and 68 + 36 = 104).