%I #31 Jun 25 2022 21:43:19

%S 4,12,24,36,50,72,98,120,144,180,220,252,286,336,375,416,459,504,570,

%T 640,693,748,805,864,950,1014,1080,1176,1276,1350,1426,1536,1617,1700,

%U 1785,1872,1998,2090,2184,2280,2378,2520,2666,2772,2880,2990,3102

%N a(n) = n*(n-th composite number).

%C Complement of A171521. - _Jaroslav Krizek_, Dec 13 2009

%H Harvey P. Dale, <a href="/A071228/b071228.txt">Table of n, a(n) for n = 1..1000</a>

%F a(n) = n * A002808(n). - _Jaroslav Krizek_, Dec 13 2009

%e a(1)= 1*4, a(2)= 2*6, a(3)= 3*9, a(4) = 4*10.

%p count := 1: for i from 2 to 100 do if isprime(i) then else printf(`%d,`,i*count); count := count+1 fi: od: # _James A. Sellers_, May 28 2002

%t Module[{cn=Select[Range[70],CompositeQ]},Times@@@Thread[{cn, Range[ Length[ cn]]}]] (* _Harvey P. Dale_, Nov 13 2014 *)

%o (PARI) lista(nn) = {my(nc = 0); forcomposite(c=1, nn, nc ++; print1(c*nc, ", "););} \\ _Michel Marcus_, Aug 31 2019

%Y Cf. A002808, A033286, A171521.

%Y Partial sums of A092930.

%K nonn

%O 1,1

%A _Amarnath Murthy_, May 17 2002

%E More terms from _James A. Sellers_, May 28 2002

%E Edited by _N. J. A. Sloane_, Jul 02 2008 at the suggestion of _R. J. Mathar_