Real part of the sum of divisors function sigma(n) generalized for Gaussian integers.

Terms

a(0) =1a(1) =2a(2) =4a(3) =-4a(4) =4a(5) =8a(6) =8a(7) =-8a(8) =13a(9) =-16a(10) =12a(11) =-16a(12) =6a(13) =16a(14) =16a(15) =16a(16) =6a(17) =26a(18) =20a(19) =-56a(20) =32a(21) =24a(22) =24a(23) =-32a(24) =-36a(25) =-42a(26) =40a(27) =-32a(28) =8a(29) =-64