a(n) = p(n)*(p(n)-1)/2 where p(n) = upper member of n-th pair of twin primes.

Terms

a(0) =10a(1) =21a(2) =78a(3) =171a(4) =465a(5) =903a(6) =1830a(7) =2628a(8) =5253a(9) =5886a(10) =9591a(11) =11325a(12) =16290a(13) =18528a(14) =19701a(15) =26106a(16) =28920a(17) =36585a(18) =39903a(19) =48828a(20) =60726a(21) =88410a(22) =93528a(23) =106953a(24) =136503a(25) =162735a(26) =180300a(27) =191271a(28) =206403a(29) =218130