One fifth of the sum of the first n primes, when an integer.

Terms

a(0) =1a(1) =2a(2) =20a(3) =32a(4) =88a(5) =212a(6) =296a(7) =344a(8) =1070a(9) =1166a(10) =1374a(11) =1655a(12) =2248a(13) =2698a(14) =3368a(15) =3730a(16) =3916a(17) =4936a(18) =5160a(19) =5388a(20) =6725a(21) =6983a(22) =8788a(23) =11338a(24) =12382a(25) =12923a(26) =13480a(27) =15026a(28) =16244a(29) =17717