1 is in the sequence because the 1st primes of the forms 6*k1 and 6*k+1(6*11=5 and 6*1+1=7, respectively) are a pair of twin primes;
2 is in the sequence because the 2nd primes (6*21=11 and 6*2+1=13) are a pair of twin primes;
3 is in the sequence because the 3rd primes (6*31=17 and 6*3+1=19) are a pair of twin primes;
6 is in the sequence because the 6th primes (6*71=41 and 6*7+1=43) are a pair of twin primes;
24 is in the sequence because the 24th primes (6*381=227 and 6*38+1=229) are a pair of twin primes.
