A113521 a(n) = largest nonprime nonnegative integer < c(n) which is coprime to c(n), where c(n) is the n-th composite positive integer.

1, 1, 1, 8, 9, 1, 9, 14, 15, 1, 9, 20, 21, 1, 24, 25, 26, 27, 1, 27, 32, 33, 34, 35, 35, 38, 39, 25, 39, 44, 45, 35, 48, 49, 50, 51, 49, 54, 55, 56, 57, 49, 57, 62, 63, 64, 65, 65, 68, 69, 65, 69, 74, 75, 76, 77, 77, 80, 81, 65, 84, 85, 86, 87, 77, 90, 91, 92, 93, 94, 95, 95, 98