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A082457 a(n) = gcd(1+2n, A057643(1+2n)). 3

%I #12 Mar 15 2018 05:01:34

%S 1,1,1,1,1,1,3,1,1,1,1,1,1,1,1,3,1,1,1,1,1,15,1,1,3,1,1,1,1,1,1,1,1,3,

%T 1,1,3,1,1,1,1,1,3,1,7,1,5,1,3,1,1,3,1,1,1,1,1,1,1,1,3,1,1,1,1,1,15,1,

%U 1,3,1,5,1,1,1,9,1,1,3,1,1,3,1,1,1,1,1,3,1,1,1,1,1,7,1,1,15,1,1,1,1,1,3,1,1

%N a(n) = gcd(1+2n, A057643(1+2n)).

%C This and A066715 are mostly equal; for differences see A083344.

%e n=22: 2n+1=45, A057643(45)=5520, a(22)=gcd(45,5520)=15 while A066715(45)=3.

%t di[x_] := Apply[LCM, Divisors[x]+1] Table[GCD[2*w+1, di[1+2*w]], {w, 1, 2048}];

%Y Cf. A057643, A066715, A000203, A083344.

%K nonn

%O 1,7

%A _Labos Elemer_, Apr 25 2003

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Last modified April 25 10:51 EDT 2024. Contains 371967 sequences. (Running on oeis4.)