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A016084 a(n+1) = a(n) + its digital root. 1
5, 10, 11, 13, 17, 25, 32, 37, 38, 40, 44, 52, 59, 64, 65, 67, 71, 79, 86, 91, 92, 94, 98, 106, 113, 118, 119, 121, 125, 133, 140, 145, 146, 148, 152, 160, 167, 172, 173, 175, 179, 187, 194, 199, 200, 202, 206, 214, 221, 226, 227, 229, 233, 241, 248 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Index entries for linear recurrences with constant coefficients, signature (2,-1,-1,2,-1).

FORMULA

G.f.: x*(5+2*x^4+6*x^3-4*x^2)/((x+1)*(x^2-x+1)*(x-1)^2) [From Maksym Voznyy (voznyy(AT)mail.ru), Aug 11 2009]

MATHEMATICA

dr[n_]:=NestWhile[Total[IntegerDigits[#]]&, n, #>9&]; NestList[#+dr[#]&, 5, 60] (* or *) LinearRecurrence[{2, -1, -1, 2, -1}, {5, 10, 11, 13, 17}, 90] (* Harvey P. Dale, Aug 15 2017 *)

CROSSREFS

Sequence in context: A242994 A070791 A173901 * A007618 A004748 A038030

Adjacent sequences:  A016081 A016082 A016083 * A016085 A016086 A016087

KEYWORD

nonn,base

AUTHOR

Robert G. Wilson v

EXTENSIONS

G.f. proposed by Maksym Voznyy checked and corrected by R. J. Mathar, Sep 16 2009.

STATUS

approved

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Last modified August 3 05:55 EDT 2020. Contains 336197 sequences. (Running on oeis4.)