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A342773 Numbers k such that k + sum of digits of k is a proper prime power.

%I A342773 #11 Mar 23 2021 05:41:13
%S A342773 2,4,8,17,18,25,38,72,118,121,161,234,245,275,329,347,521,614,720,830,
%T A342773 944,998,1016,1318,1355,1664,1829,2041,2169,2183,2189,2384,2786,3115,
%U A342773 3464,3710,4082,4472,4891,4900,5027,5315,6230,6543,6836,7889,8173,10190,10592,10601,11435,11858,12154,12752
%N A342773 Numbers k such that k + sum of digits of k is a proper prime power.
%C A342773 Numbers k such that A062028(k) is in A246547.
%C A342773 Proper prime powers in the sequence include 4, 8, 25, 121.  Are there any others?
%H A342773 Robert Israel, <a href="/A342773/b342773.txt">Table of n, a(n) for n = 1..1001</a>
%e A342773 a(4) = 17 is a term because 17+1+7 = 25 = 5^2.
%p A342773 filter:= proc(n) local s,F;
%p A342773    s:= n + convert(convert(n,base,10),`+`);
%p A342773    F:= ifactors(s)[2];
%p A342773    nops(F)=1 and F[1][2]>1
%p A342773 end proc:
%p A342773 select(filter, [$1..20000]);
%o A342773 (PARI) isok(k) = isprimepower(k + sumdigits(k)) > 1; \\ _Michel Marcus_, Mar 22 2021
%Y A342773 Cf. A062028, A246547. Contains A242368.
%K A342773 nonn,base
%O A342773 1,1
%A A342773 _J. M. Bergot_ and _Robert Israel_, Mar 21 2021