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%I #24 Feb 14 2025 08:26:44
%S 5,8,41,47057
%N Numbers k such that A003415(sigma(k)) = k, where A003415 is the arithmetic derivative, and sigma is the sum of divisors of n.
%C a(5) > 2^33, if it exists.
%C Terms of this sequence and A230165 group into pairs (m, sigma(m)), where m is a term of this sequence and sigma(m) is a term of A230165. - _Max Alekseyev_, Feb 13 2025
%F a(n) = A003415(A230165(n)). - _Max Alekseyev_, Feb 13 2025
%Y Fixed points of A342925.
%Y Positions of 0's in A342926.
%Y Subsequence of A343217.
%Y Cf. A000203, A003415, A229342, A230164, A230165, A347889.
%K nonn,more,hard
%O 1,1
%A _Antti Karttunen_, Apr 08 2021