a(n) is the sum of the Wieferich and Wall-Sun-Sun residues of prime(n).

Terms

a(0) =3a(1) =6a(2) =20a(3) =35a(4) =110a(5) =78a(6) =493a(7) =114a(8) =736a(9) =783a(10) =961a(11) =518a(12) =2542a(13) =2752a(14) =2820a(15) =3392a(16) =1062a(17) =5124a(18) =1139a(19) =4047a(20) =8322a(21) =5372a(22) =5727a(23) =979a(24) =9118a(25) =19089a(26) =8343a(27) =3959a(28) =10137a(29) =16159