a(n) = 65 - 100n
First five terms:
a(1) = 65 - 100x1 = - 35
a(2) = 65 - 100x2 = 65 - 200 = -135
a(3) = 65 - 100(3) = 65 - 300 = -235
a(4) = 65 - 100(4) = 65 - 400 = -335
a(5) = 65 - 100(5) = 65 - 500 = -435
Term 39
a(39) = 65 -100(39) = 65 - 3900 = -3835
a(n) = 11/8 + (1/2)n
First five terms:
a(1) = 11/8 + (1/2)1 = 11/8 + 1/2 = 15/8
a(2) = 11/8 + (1/2)2 = 11/8 + 2/2 = 19/8
a(3) = 11/8 + (1/2)3 = 23/8
a(4) = 11/8 + (1/2)4 = 27/8
a(5) = 11/8 + (1/2)5 = 31/8
Term 23
a(23) = 11/8 + (1/2)23 = 103/8