A164280 - OEIS

%I #6 Sep 08 2022 08:45:47

%S 1,64,800,1452,207143,14934568,18656679,42721785,889239450,1991045973,

%T 6684665064,11847007536,127880982508860,262907426075600,

%U 435646635220423,58536266213035868,1777764795352216572,5690843954660983949,190101452851104748107,71537286176000166753366

%N a(n) is the sum of the first A129749(n) nonprimes.

%C A variant of A050247 for nonprimes.

%F a(n) = sum_{i=1..A129749(n)} A018252(i).

%e A129749(4) = 44; sum of first 44 nonprimes is 1452, so a(4) = 1452.

%o (Magma) S:=[]; a:=0; c:=0; for n in [1..20000000] do if not IsPrime(n) then a+:=n; c+:=1; if a mod c eq 0 then Append(~S, a); end if; end if; end for; S;

%Y Cf. A129749, A050247, A018252, A160758.

%K nonn

%O 1,2

%A _Klaus Brockhaus_, Aug 11 2009

%E a(16)-a(19) from _Donovan Johnson_, Sep 19 2009

%E a(20) from _Donovan Johnson_, Jun 21 2011