The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A164280 a(n) is the sum of the first A129749(n) nonprimes. 2
 1, 64, 800, 1452, 207143, 14934568, 18656679, 42721785, 889239450, 1991045973, 6684665064, 11847007536, 127880982508860, 262907426075600, 435646635220423, 58536266213035868, 1777764795352216572, 5690843954660983949, 190101452851104748107, 71537286176000166753366 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS A variant of A050247 for nonprimes. LINKS FORMULA a(n) = sum_{i=1..A129749(n)} A018252(i). EXAMPLE A129749(4) = 44; sum of first 44 nonprimes is 1452, so a(4) = 1452. PROG (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; CROSSREFS Cf. A129749, A050247, A018252, A160758. Sequence in context: A190532 A181889 A236182 * A232001 A185299 A250281 Adjacent sequences:  A164277 A164278 A164279 * A164281 A164282 A164283 KEYWORD nonn AUTHOR Klaus Brockhaus, Aug 11 2009 EXTENSIONS a(16)-a(19) from Donovan Johnson, Sep 19 2009 a(20) from Donovan Johnson, Jun 21 2011 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified September 19 07:08 EDT 2021. Contains 347554 sequences. (Running on oeis4.)