Infinite sum of the natural numbers, compacted (see comments for an explanation).

Terms

a(0) =3a(1) =7a(2) =11a(3) =24a(4) =46a(5) =29a(6) =376a(7) =134a(8) =73a(9) =158a(10) =13504a(11) =1388a(12) =718a(13) =734a(14) =373a(15) =758a(16) =328192a(17) =1667a(18) =55456a(19) =3602a(20) =123712a(21) =2063a(22) =4138a(23) =8324a(24) =68896a(25) =4442a(26) =3831808a(27) =3579392a(28) =8017a(29) =521408