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%I #10 Aug 15 2017 13:02:40
%S 5,10,11,13,17,25,32,37,38,40,44,52,59,64,65,67,71,79,86,91,92,94,98,
%T 106,113,118,119,121,125,133,140,145,146,148,152,160,167,172,173,175,
%U 179,187,194,199,200,202,206,214,221,226,227,229,233,241,248
%N a(n+1) = a(n) + its digital root.
%H Harvey P. Dale, <a href="/A016084/b016084.txt">Table of n, a(n) for n = 1..1000</a>
%H <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1,-1,2,-1).
%F 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]
%t 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 *)
%K nonn,base
%O 1,1
%A _Robert G. Wilson v_
%E G.f. proposed by Maksym Voznyy checked and corrected by R. J. Mathar, Sep 16 2009.
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