This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A164280 #6 Sep 08 2022 08:45:47
%S A164280 1,64,800,1452,207143,14934568,18656679,42721785,889239450,1991045973,
%T A164280 6684665064,11847007536,127880982508860,262907426075600,
%U A164280 435646635220423,58536266213035868,1777764795352216572,5690843954660983949,190101452851104748107,71537286176000166753366
%N A164280 a(n) is the sum of the first A129749(n) nonprimes.
%C A164280 A variant of A050247 for nonprimes.
%F A164280 a(n) = sum_{i=1..A129749(n)} A018252(i).
%e A164280 A129749(4) = 44; sum of first 44 nonprimes is 1452, so a(4) = 1452.
%o A164280 (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 A164280 Cf. A129749, A050247, A018252, A160758.
%K A164280 nonn
%O A164280 1,2
%A A164280 _Klaus Brockhaus_, Aug 11 2009
%E A164280 a(16)-a(19) from _Donovan Johnson_, Sep 19 2009
%E A164280 a(20) from _Donovan Johnson_, Jun 21 2011