A045646 - OEIS (original) (raw)

COMMENTS

This is also the smallest n such that digit sum of n = previous term. - Dominick Cancilla, Aug 09 2010

REFERENCES

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

FORMULA

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

MATHEMATICA

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

EXTENSIONS

Next term is 1 followed by 2222222222222222222222 9s.