This is my third batch of sequence puzzles that are nasty and hard to solve; yet, each of them has a clear and justifiable solution.
Sequence 1:
2, 4, 4, 3, ?, ?, 3, 4, 2, 4, 3, 4, 2, 2, 3, 4, 4, 3, ?, ?, ...
Sequence 2:
?, ?, ?, J, J, ?, A, M, ?, J, J, Z, M, F, J, A, A, U, R, J, C, G, B, G, W, T, W, W, W, ...
Sequence 3:
??, ??, Ca, Cl, Ne, Ga, ??, ??, ??, Ti, ??, Ne, ??, ??, ??, Au, Lu, ...
Sequence 4:
0.06, 0.82, 1.00, 0.11, ??, ??, 14.6, 17.2
Sequence 5:
A, E, A, P, A, ?, U, ?, E, ?, ?, ...