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A083447 a(n) = floor( n*R(n)/(n+R(n))), where R(n) is the digit reversal of n (A004086). 1

%I #19 May 28 2021 13:43:41

%S 1,1,2,2,3,3,4,4,0,5,7,9,10,11,12,13,14,15,1,7,11,13,15,16,18,19,20,

%T 22,2,9,13,16,18,21,22,24,26,27,3,10,15,18,22,24,26,28,30,32,4,11,16,

%U 21,24,27,30,32,34,36,5,12,18,22,26,30,33,35,37,40,6,13,19,24,28,32,35,38,41

%N a(n) = floor( n*R(n)/(n+R(n))), where R(n) is the digit reversal of n (A004086).

%H Vincenzo Librandi, <a href="/A083447/b083447.txt">Table of n, a(n) for n = 2..1000</a>

%e a(17) = floor(17*71/(17+71)) = floor(1207/88) = 13.

%t drev[n_]:=Module[{dr=FromDigits[Reverse[IntegerDigits[n]]]},Floor[ (dr*n)/ (dr+n)]]; Array[drev,80,2] (* _Harvey P. Dale_, Apr 26 2014 *)

%Y Cf. A004086.

%K base,easy,nonn

%O 2,3

%A _Amarnath Murthy_ and Meenakshi Srikanth (menakan_s(AT)yahoo.com), May 01 2003

%E More terms from _Jason Earls_, May 23 2004

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Last modified August 25 17:04 EDT 2024. Contains 375442 sequences. (Running on oeis4.)