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7-Kaprekar numbers.
4

%I #8 Mar 09 2020 14:45:14

%S 1,627615,4444444,4927941,5072059,5555556,9372385,9999999

%N 7-Kaprekar numbers.

%C No n-Kaprekar number k can have more than n digits because then the number to the left of the plus sign would have more digits than k itself, meaning the sum will always be greater than k.

%e 627615 is in this sequence because inserting a + before the 7th digit from the right of 627615^2 = 393900588225 yields 39390 + 0588225, which equals 627615 (the starting number).

%Y Cf. A006886, A037042, A053394, A053395, A053396, A053397.

%K nonn,fini,full,base

%O 1,2

%A _Eric Fox_, Mar 09 2020