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A325975 a(n) = gcd(A325977(n), A325978(n)). 23

%I #13 Jun 06 2019 21:58:46

%S 1,1,1,1,1,6,1,1,1,2,1,4,1,2,3,1,1,3,1,2,1,2,1,12,1,2,1,4,1,6,1,1,3,2,

%T 1,1,1,2,1,2,1,6,1,4,3,2,1,4,1,1,3,2,1,6,1,8,1,2,1,12,1,2,1,1,1,6,1,2,

%U 3,2,1,3,1,2,1,4,1,6,1,2,1,2,1,4,1,2,3,4,1,18,7,4,1,2,5,12,1,1,3,1,1,6,1,2,3

%N a(n) = gcd(A325977(n), A325978(n)).

%C See comments in A325979 and A325981.

%H Antti Karttunen, <a href="/A325975/b325975.txt">Table of n, a(n) for n = 1..65537</a>

%F a(n) = gcd(A325977(n), A325978(n)).

%F a(n) = (1/2)*gcd(A034460(n)+A325313(n), A325814(n)+A325314(n)).

%o (PARI)

%o A048250(n) = factorback(apply(p -> p+1,factor(n)[,1]));

%o A162296(n) = sumdiv(n, d, d*(1-issquarefree(d)));

%o A325313(n) = (A048250(n) - n);

%o A325314(n) = (n - A162296(n));

%o A034448(n) = { my(f=factorint(n)); prod(k=1, #f~, 1+(f[k, 1]^f[k, 2])); }; \\ After code in A034448

%o A034460(n) = (A034448(n) - n);

%o A048146(n) = (sigma(n)-A034448(n));

%o A325814(n) = (n-A048146(n));

%o A325977(n) = ((A034460(n)+A325313(n))/2);

%o A325978(n) = ((A325314(n)+A325814(n))/2);

%o A325975(n) = gcd(A325977(n), A325978(n));

%o \\ Or alternatively, as:

%o A325975(n) = (1/2)*gcd((A034460(n)+A325313(n)),(A325814(n)+A325314(n)));

%Y Cf. A034460, A048107, A325313, A325314, A325814, A325973, A325974, A325977, A325978, A325979, A325981.

%Y Cf. also A009194, A325385, A325813, A326046, A326047, A326048, A326056, A326057, A326060, A326062.

%K nonn

%O 1,6

%A _Antti Karttunen_, Jun 02 2019

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Last modified July 17 23:27 EDT 2024. Contains 374377 sequences. (Running on oeis4.)