Problem
COM-B1-M03-P015 Six Nonconsecutive Numbers
#15
★★★☆☆ Level 3 of 5
How many \(6\)-element subsets of \(\{1,\ldots,12\}\) contain no consecutive numbers?
Use the shifting formula for \(k=6\).
For chosen \(a_1<\cdots
Shows how a strong restriction leaves few options.