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%I #14 Aug 11 2019 13:23:38
%S 4,6,9,36,180,186,1302,1310,11790,11800,11811,11823,11836,11850,11865,
%T 11881,11898,11916,11935,11955,11976,11998,12021,12045,12070,12096,
%U 12123,12151,12180,12210,378510,378542,378575,378609,378644,378680
%N a(1)=4. a(n) = a(n-1) + n, if a(n-1)+n is composite. Otherwise a(n) = a(n-1)*n.
%C Each term is composite.
%H Harvey P. Dale, <a href="/A175459/b175459.txt">Table of n, a(n) for n = 1..1000</a>
%p A175459 := proc(n) option remember; if n =1 then 4; else if isprime( procname(n-1)+n) then procname(n-1)*n; else procname(n-1)+n ; end if; end if; end proc:
%p seq(A175459(n),n=1..120) ; # _R. J. Mathar_, May 28 2010
%t nxt[{n_,a_}]:={n+1,If[CompositeQ[a+n+1],a+n+1,a(n+1)]}; NestList[nxt,{1,4},40][[All,2]] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Aug 11 2019 *)
%K nonn
%O 1,1
%A _Leroy Quet_, May 20 2010
%E More terms from _R. J. Mathar_, May 28 2010
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