First element r of (-1)sigma sociable triple (r,s,t): s=(-1)sigma(r), t=(-1)sigma(s), r=(-1)sigma(t), where if x=Product p(i)^r(i), then (-1)sigma(x)=Product(-1+(Sum p(i)^s(i), s(i)=1 to r(i))).
A049057
First element r of (-1)sigma sociable triple (r,s,t): s=(-1)sigma(r), t=(-1)sigma(s), r=(-1)sigma(t), where if x=Product p(i)^r(i), then (-1)sigma(x)=Product(-1+(Sum p(i)^s(i), s(i)=1 to r(i))).
Terms
- a(0) =20a(1) =40a(2) =52a(3) =60a(4) =104a(5) =120a(6) =156a(7) =312a(8) =480a(9) =488a(10) =780a(11) =1248a(12) =1464a(13) =1560a(14) =5856a(15) =6240a(16) =7320a(17) =7680a(18) =8168a(19) =9744a(20) =13260a(21) =19968a(22) =24504a(23) =26520a(24) =29280a(25) =93696a(26) =98016a(27) =99840a(28) =106080a(29) =122520
External references
- oeis: A049057