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a(n) = gcd(n, A066260(n)).
2

%I #26 Jan 30 2022 15:55:44

%S 1,2,3,4,1,6,1,8,9,2,1,12,1,2,3,16,1,18,1,4,3,2,1,24,1,2,27,4,1,6,1,

%T 32,3,2,1,36,1,2,3,8,1,6,1,4,9,2,1,48,1,2,3,4,1,54,5,8,3,2,1,12,1,2,9,

%U 64,1,6,1,4,3,2,1,72,1,2,3,4,1,6,1,16,81,2,1,12,1,2,3,8,1,18,1,4,3,2,5,96

%N a(n) = gcd(n, A066260(n)).

%C Same as A065331 through a(54); A065331(55)=1, but a(55)=5. - _Jon E. Schoenfield_, Jan 28 2022

%H Harry J. Smith, <a href="/A066262/b066262.txt">Table of n, a(n) for n = 1..1000</a>

%o (PARI) Composite(n) = { my(k=n + primepi(n) + 1); while (k != n + primepi(k) + 1, k = n + primepi(k) + 1); return(k) }

%o { for (n=1, 100, my(f=factor(n), a=1); for (i=1, matsize(f)[1], a*=Composite(primepi(f[i, 1]))^f[i, 2]); a=gcd(n, a); print1(a, ", ") ) } \\ _Harry J. Smith_, Feb 07 2010

%Y Cf. A066260.

%Y Different from A065331.

%K nonn

%O 1,2

%A _Reinhard Zumkeller_, Dec 10 2001