A164280 a(n) is the sum of the first A129749(n) nonprimes.

1, 64, 800, 1452, 207143, 14934568, 18656679, 42721785, 889239450, 1991045973, 6684665064, 11847007536, 127880982508860, 262907426075600, 435646635220423, 58536266213035868, 1777764795352216572, 5690843954660983949, 190101452851104748107, 71537286176000166753366

Offset

1,2

Comments

A variant of A050247 for nonprimes.

Links

Table of n, a(n) for n=1..20.

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