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%I #23 Nov 07 2016 11:12:33
%S 1,5,9,13,35,57,79,101,105,505,509,909,913,323,327,727,731,141,145,
%T 545,549,949,953,363,367,767,771,181,185,585,589,989,993,403,308,807,
%U 712,221,126,625,530,39,97,83,42,28,86,72,31,17,75,61,20,6,10,5,9,13,35,57,79,101,105,505,509,909,913,323,327,727,731
%N Start with 1 and repeatedly reverse the decimal digits and add 4 to get the next term.
%H N. J. A. Sloane and others, <a href="/wiki/Sequences_of_RADD_type">Sequences of RADD type</a>, OEIS wiki.
%H <a href="/index/Rec#order_54">Index entries for linear recurrences with constant coefficients</a>, signature (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1).
%F After one step enters a cycle of length 54: see A117827, A117830.
%p read transforms; t1:=[1]; for n from 1 to 80 do t1:=[op(t1),4+digrev(t1[n])]; od: # _N. J. A. Sloane_
%t f[n_] := 4 + FromDigits@ Reverse@ IntegerDigits@n; NestList[ f@# &, 1, 57] (* and *)
%t (* to view the cycle *) NestWhileList[ f@# &, 1, UnsameQ, All] (* _Robert G. Wilson v_, May 09 2006 *)
%o (PARI) a(n)=if(n>1, my(t=6); for(k=1,n%54, t=fromdigits(Vecrev(digits(t)))+4); t, 1) \\ _Charles R Greathouse IV_, Nov 07 2016
%Y Cf. A117827, A117829, A117830.
%K nonn,base,easy
%O 1,2
%A Luc Stevens (lms022(AT)yahoo.com), Apr 06 2006
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