a(n) = sum_{k=1..n} prime(k)*prime(k+1).

Terms

a(0) =6a(1) =21a(2) =56a(3) =133a(4) =276a(5) =497a(6) =820a(7) =1257a(8) =1924a(9) =2823a(10) =3970a(11) =5487a(12) =7250a(13) =9271a(14) =11762a(15) =14889a(16) =18488a(17) =22575a(18) =27332a(19) =32515a(20) =38282a(21) =44839a(22) =52226a(23) =60859a(24) =70656a(25) =81059a(26) =92080a(27) =103743a(28) =116060a(29) =130411