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%I #6 Nov 22 2019 01:21:07
%S 0,1,2,3,4,13,18,28,118,257,289,308,353,419,4890,4891,9113,16387,
%T 66562,322217,1874374,172449032,268533762,338749352,2204944815,
%U 2204944816,2415951874,3250054360,3250054361,3264337734,4424304070,4424304071
%N Base 5 perfect digital invariants (written in base 10): numbers equal to the sum of the k-th powers of their base-5 digits, for some k.
%C Whenever a(n) is a multiple of 5, then a(n+1) = a(n) + 1 is also a base 5 perfect digital invariant, with the same exponent k. - _M. F. Hasler_, Nov 21 2019
%H Joseph Myers, <a href="/A162222/b162222.txt">Table of n, a(n) for n=1..1640</a> (complete to 700 base 5 digits)
%o (PARI) select( {is_A162222(n, b=5)=n<b||forstep(k=logint(n,max(vecmax(b=digits(n, b)), 2)), 2, -1, my(t=vecsum([d^k|d<-b])); t>n||return(t==n))}, [0..10^5]) \\ _M. F. Hasler_, Nov 21 2019
%Y Cf. A162223 (corresponding exponents), A010346 (restriction to power = number of digits), A033837, A162224. In other bases: A162216 (base 3), A162219 (base 4), A162225 (base 6), A162228 (base 7), A162231 (base 8), A162234 (base 9), A023052 (base 10).
%K base,nonn
%O 1,3
%A _Joseph Myers_, Jun 28 2009
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