>>40582687
hmmmm lets see
so there's 15 ways to choose 5 consecutive items out of a list of 20
so the number of permutations is 15 * (20 choose 15)?
Multiply that by 2 since we're interested in heads or tails to give us the total number of permutations satisfying the condition
divided by 2^20 total permutations?
according to my math that seems to be about a probability of 0.44