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Smallest k such that 2ik+1 is squarefree for 1<=i<=n.
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%I #6 Mar 30 2012 18:39:02

%S 1,1,1,5,5,5,5,9,9,9,9,9,9,9,9,63,63,63,63,63,63,63,63,135,135,135,

%T 135,135,135,135,135,135,135,135,135,135,135,135,135,135,135,135,135,

%U 735,735,735,945,945,945,1155,1155,1155,1155,1155,1155,1155

%N Smallest k such that 2ik+1 is squarefree for 1<=i<=n.

%o (PARI) for(n=1,56,s=1; while(sum(i=1,n,issquarefree(2*i*s+1))<n,s++); print1(s, ","))

%K easy,nonn

%O 1,4

%A _Benoit Cloitre_, May 31 2002