A068630 a(0)=0; a(n) = n + a(n-1) if gcd(n,a(n-1)) = 1 or a(n-1) = 0; a(n) = a(n-1) - n if n divides a(n-1), otherwise a(n) = a(n-1).
0, 1, 3, 0, 4, 9, 9, 16, 8, 17, 27, 38, 38, 51, 65, 65, 81, 98, 98, 117, 137, 158, 158, 181, 205, 205, 231, 231, 231, 260, 260, 291, 323, 356, 356, 391, 427, 464, 464, 503, 543, 584, 584, 627, 627, 627, 673, 720, 672, 672, 672, 672, 672, 725, 779, 834, 834, 834
Offset: 0
Extensions
Offset and a(55)-a(57) corrected by Gionata Neri, Mar 23 2017