45, 44, 36, 32, 31, 26, 22, 21, ?

I do not know if this is logical. If we split the series into alternate sub series.

45, 36, 31, 22, ? and 44, 32, 26, 21 and the relation in first series alternate reduction by 5 or 9 and next adjacent second series number is lower than first series number by 1, 4, 5 repeatedly then first series could be

87, 78, 73, 64, 59, 50, 45, 36, 31, 22, 17, 8, 3 and second series would be

86, 74, 68, 63, 55, 45, 44, 32, 26, 21, 13, 3, 2 the total series would be

87, 86, 78, 74, 73, 68, 64, 63, 59, 55, 50, 45, 45, 44, 36, 32, 31, 26, 22, 21, 17, 13, 8, 3, 3, 2

In this case also the next number in the sequence is 17.