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Alternative version of A006050.
5

%I #15 Mar 08 2020 22:57:53

%S 1,10,19,199,19999999999999999999999

%N Alternative version of A006050.

%C This is also the smallest n such that digit sum of n = previous term. - _Dominick Cancilla_, Aug 09 2010

%D H. J. Hindin, The additive persistence of a number, J. Rec. Math., 7 (No. 2, 1974), 134-135.

%H N. J. A. Sloane, <a href="http://neilsloane.com/doc/persistence.html">The persistence of a number</a>, J. Recreational Math., 6 (1973), 97-98.

%F For n > 1, a(n) = 2*10^((a(n-1)-1)/9) - 1.

%t Join[{1},NestList[2*10^((#-1)/9)-1&,10,3]] (* _Harvey P. Dale_, Sep 20 2011 *)

%Y Cf. A003001, A006050.

%K nonn,base,nice

%O 0,2

%A _N. J. A. Sloane_

%E Next term is 1 followed by 2222222222222222222222 9s.