A062562 - OEIS

%I #15 Jul 18 2022 16:38:25

%S 0,1,-2,-6,-6,-12,0,-8,-8,-8,10,-2,-2,-16,8,32,32,14,14,-6,-6,26,62,

%T 38,38,38,80,80,80,50,-22,-54,-54,-6,48,96,96,58,118,174,174,132,36,

%U -8,-8,-8,64,16,16,16,16,88,88,34,34,106,106,186,276,216,216,154,250,250,250,334,190,122,122,218,74,2,2,-72,42,42,42

%N a(n) = Sum_{k=1..n} mu(k)*sigma(k).

%t Table[Sum[MoebiusMu[k]DivisorSigma[1,k],{k,n}],{n,0,80}] (* _Harvey P. Dale_, Nov 08 2011 *)

%o (PARI) s=[]; for(n=0,130,s=concat(s,sum(k=1,n,moebius(k)*sigma(k)))); s

%Y Partial sums of A063441.

%K sign

%O 0,3

%A _Jason Earls_, Jul 03 2001

%E Corrected by _Harvey P. Dale_, Nov 08 2011