a(1)=0; thereafter a(n) = (n-1)*sigma(n)-n*sigma(n-1) where sigma is the sum-of-divisors function A000203.
A335153
a(1)=0; thereafter a(n) = (n-1)*sigma(n)-n*sigma(n-1) where sigma is the sum-of-divisors function A000203.
Terms
- a(0) =0a(1) =1a(2) =-1a(3) =5a(4) =-11a(5) =24a(6) =-36a(7) =41a(8) =-31a(9) =32a(10) =-78a(11) =164a(12) =-196a(13) =116a(14) =-24a(15) =81a(16) =-239a(17) =339a(18) =-381a(19) =398a(20) =-242a(21) =52a(22) =-300a(23) =804a(24) =-756a(25) =244a(26) =-94a(27) =392a(28) =-784a(29) =1188
External references
- oeis: A335153