a(n) = sum of the numbers between the two n's in A026370.

Terms

a(0) =5a(1) =13a(2) =25a(3) =61a(4) =85a(5) =144a(6) =180a(7) =262a(8) =310a(9) =362a(10) =418a(11) =539a(12) =607a(13) =751a(14) =831a(15) =915a(16) =1003a(17) =1186a(18) =1286a(19) =1492a(20) =1604a(21) =1720a(22) =1840a(23) =2085a(24) =2217a(25) =2485a(26) =2629a(27) =2920a(28) =3076a(29) =3390