62342domain: NAppears in sequencesa(n) is the number of n-tosses having a run of 3 or more heads or a run of 3 or more tails for a fair coin (i.e., probability is a(n)/2^n).at n=15A167821a(n) = Sum_{j=1..n*(n-1)} (n*j mod (n+j)).at n=20A309341