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%I #28 Nov 03 2023 11:05:59
%S 3,6,12,33,66,132,363,726,1353,4884,9768,18447,92928,175857,934428,
%T 1758867,9447438,17794887,96644658,182289327,906271608,1712444217,
%U 8836886388,17673772776,85401510447,159803020905,668823329856,1327746658722,3606313135953,7201626272016
%N Trajectory of 3 under map x->x + (x-with-digits-reversed).
%C Normally one stops as soon as a palindrome is reached.
%C A Reverse and Add! sequence.
%H Alois P. Heinz, <a href="/A033648/b033648.txt">Table of n, a(n) for n = 0..1000</a> (first 251 terms from Reinhard Zumkeller)
%H <a href="/index/Res#RAA">Index entries for sequences related to Reverse and Add!</a>
%p a:= proc(n) option remember; `if`(n=0, 3, (h-> h+ (s->
%p parse(cat(s[-i]$i=1..length(s))))(""||h))(a(n-1)))
%p end:
%p seq(a(n), n=0..40); # _Alois P. Heinz_, Jun 18 2014
%t NestList[ # + FromDigits@Reverse@IntegerDigits@# &, 3, 29] (* _Robert G. Wilson v_, Dec 16 2005 *)
%o (Haskell)
%o a033648 n = a033648_list !! n
%o a033648_list = iterate a056964 3 -- _Reinhard Zumkeller_, Sep 22 2011
%Y Cf. A006960, A001127, A033649, A033650, A033651.
%Y Cf. A056964, A004086.
%Y Row n=3 of A243238.
%K nonn,base
%O 0,1
%A _N. J. A. Sloane_.
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