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%I #14 Nov 22 2019 01:14:21
%S 0,1,2,3,4,5,6,7,8,27,28,41,50,126,127,243,244,353,468,469,1052,1824,
%T 2187,2188,8052,8295,9857,19683,19684,36804,65538,65539,177147,177148,
%U 1198372,1594323,1594324,3357009,3357010,5300099,6287267,10097892
%N Base 9 perfect digital invariants (written in base 10): numbers equal to the sum of the k-th powers of their base-9 digits, for some k.
%C Whenever a(n) is a multiple of 9, then a(n+1) = a(n) + 1 is also a base 9 perfect digital invariant, with the same exponent k. - _M. F. Hasler_, Nov 21 2019
%H Joseph Myers, <a href="/A162234/b162234.txt">Table of n, a(n) for n=1..506</a> (complete to 120 base 9 digits)
%o (PARI) select( {is_A162234(n, b=9)=n<b|| forstep(p=logint(n, max(vecmax(b=digits(n, b)),2)), 2, -1, my(t=vecsum([d^p|d<-b])); t>n|| return(t==n))}, [0..10^5]) \\ _M. F. Hasler_, Nov 21 2019
%Y Cf. A162235 (corresponding exponents), A010353 (restriction to power = number of digits), A033841, A162236. In other bases: A162216 (base 3), A162219 (base 4), A162222 (base 5), A162225 (base 6), A162228 (base 7), A162231 (base 8), A023052 (base 10).
%K base,nonn
%O 1,3
%A _Joseph Myers_, Jun 28 2009
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