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A045646 Alternative version of A006050. 5
1, 10, 19, 199, 19999999999999999999999 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

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

REFERENCES

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

LINKS

Table of n, a(n) for n=0..4.

N. J. A. Sloane, The persistence of a number, J. Recreational Math., 6 (1973), 97-98.

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 *)

CROSSREFS

Cf. A003001, A006050.

Sequence in context: A121725 A110368 A006050 * A212594 A255529 A023916

Adjacent sequences:  A045643 A045644 A045645 * A045647 A045648 A045649

KEYWORD

nonn,base,nice

AUTHOR

N. J. A. Sloane.

EXTENSIONS

Next term is 1 followed by 2222222222222222222222 9s.

STATUS

approved

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Last modified September 17 06:52 EDT 2019. Contains 327119 sequences. (Running on oeis4.)