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%I #24 Dec 30 2023 12:35:14
%S 5798663,5555564201311,5555574497311,5555593942711,66815976110703,
%T 69437045907973255623
%N Numbers k such that k + phi(k) is a repunit.
%C Also in the sequence is 555555555555555555555556288388841217550575591423513701223. - _Robert Israel_, Aug 20 2019
%C The number 5975946235638859341313216528710061511 is also in the sequence. - _Daniel Suteu_, Aug 22 2019
%e 5798663 is a terms since phi(5798663) = 5312448 and 5798663 + 5312448 = 11111111.
%o (PARI) isok(k) = my(d=digits(k+eulerphi(k))); vecmin(d)==1 && vecmax(d)==1; \\ _Daniel Suteu_, Aug 22 2019
%Y Subsequence of A116018.
%Y Cf. A000010, A002275, A121048, A244444.
%K nonn,base,more
%O 1,1
%A _Giovanni Resta_, Aug 19 2019
%E a(5) from _Daniel Suteu_ confirmed by _Max Alekseyev_, Oct 25 2023
%E a(6) from _Max Alekseyev_, Nov 30 2023
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