sigma(n) plus the n-th prime gives a square.

Terms

a(0) =3a(1) =6a(2) =7a(3) =9a(4) =18a(5) =58a(6) =73a(7) =134a(8) =198a(9) =251a(10) =278a(11) =287a(12) =461a(13) =483a(14) =505a(15) =525a(16) =529a(17) =665a(18) =772a(19) =939a(20) =960a(21) =986a(22) =1291a(23) =1432a(24) =1463a(25) =1629a(26) =2115a(27) =2931a(28) =2991a(29) =3422