A048274 Let G be the graph with n vertices, the i-th vertex consisting of all multiples of i <= n, where edges indicate that the vertices intersect; a(n) = |n-(number of edges of G)|.
1, 1, 1, 0, 0, 3, 3, 5, 6, 9, 9, 15, 15, 18, 21, 24, 24, 30, 30, 36, 39, 42, 42, 51, 52, 55, 57, 63, 63, 75, 75, 79, 82, 85, 88, 99, 99, 102, 105, 114, 114, 126, 126, 132, 138, 141, 141, 153, 154, 160, 163, 169, 169, 178, 181, 190, 193, 196, 196, 217, 217, 220, 226
Offset: 1
Keywords
Examples
For n=6 the vertices are {1,2,3,4,5,6},{2,4,6},{3,6},{4},{5},{6}. There are 9 = 5+3+1 edges and so a(6) = |6-9| = 3.