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%I #20 Feb 01 2024 00:10:09
%S 39,587,124499
%N a(n) = smallest number m such that digitsum(m^n) < digitsum(m), or -1 if no such m exists.
%C a(n) > 0 when n is even (see MSE link).
%C a(5) > 10^12 or a(5) = -1. - _Max Alekseyev_, Jan 26 2024
%H Jeppe Stig Nielsen et al., <a href="https://math.stackexchange.com/q/1401871">Integers n for which the digit sum of n exceeds the digit sum of n^5</a>, Math StackExchange, 2015.
%e a(2) = A064399(1).
%e a(3) = A064209(1).
%e a(4) = A261439(1).
%Y Cf. A007953, A064399, A064209, A122484, A261439, A292832.
%K nonn,base,bref,hard,more
%O 2,1
%A _Max Alekseyev_, Oct 19 2023