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%I #12 May 08 2022 10:33:54
%S 1,114,618,2428,3868,11706,16012,23946,2031108,2938902,3531102,
%T 10475862,98250486,205600756
%N Numbers k for which phi(sigma(k)) + A064989(sigma(k)) is equal to phi(k) + A064989(k).
%C Numbers k such that A353747(k) = A353747(sigma(k)), or equally that A062401(k) + A350073(k) = A000010(k) + A064989(k).
%C When A003961(x) is substituted for k, the condition becomes: numbers x such that phi(A003973(x))+A326042(x) = A003972(x)+x, i.e. A353747(A003973(x)) - x = A003972(x).
%C a(15) > 1442840576, if it exists.
%H <a href="/index/O#opnseqs">Index entries for sequences where odd perfect numbers must occur, if they exist at all</a>
%H <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>
%o (PARI)
%o A064989(n) = { my(f=factor(n>>valuation(n,2))); for(i=1, #f~, f[i,1] = precprime(f[i,1]-1)); factorback(f); };
%o isA353746(n) = { my(s=sigma(n)); ((eulerphi(s)+A064989(s))==(eulerphi(n)+A064989(n))); };
%Y Cf. A000010, A000203, A062401, A064989, A350073, A353747.
%Y Cf. A003961, A003972, A003973, A326042.
%Y Cf. also A348748, A348749, A351440.
%K nonn,more
%O 1,2
%A _Antti Karttunen_, May 06 2022
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