Search: id:A049343
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%I A049343
%S A049343 0,2,9,11,18,20,29,38,45,47,90,99,101,110,119,144,146,180,182,189,
%T A049343 198,200,245,290,299,335,344,351,362,369,380,398,450,452,459,461,
%U A049343 468,470,479,488,495,497,639,729,794,839,848,900,929,954,990,999
%N A049343 Numbers n such that 2n and n^2 have same digit sum.
%C A049343 An easy way to prove that this sequence is infinite is to observe that 
               it contains all numbers of the form 10^k+1. - Stefan Steinerberger 
               (stefan.steinerberger(AT)gmail.com), Mar 31 2006
%C A049343 For n>0: digital root (A010888) of 2n or n^2 is either 4 or 9. - Reinhard 
               Zumkeller (reinhard.zumkeller(AT)gmail.com), Oct 01 2007
%D A049343 Problem 117 in Loren Larson's translation of Paul Vaderlind's book.
%H A049343 R. Zumkeller, <a href="b049343.txt">Table of n, a(n) for n = 1..101</
               a>
%F A049343 A007953(A005843(a(n))) = A007953(A000290(a(n))). - Reinhard Zumkeller 
               (reinhard.zumkeller(AT)gmail.com), Oct 01 2007
%t A049343 Select[Range[0, 1000], Sum[DigitCount[2# ][[i]]*i, {i, 1, 9}] == Sum[DigitCount[ 
               #^2][[i]]*i, {i, 1, 9}] &] - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), 
               Mar 31 2006
%Y A049343 Sequence in context: A138759 A098934 A043307 this_sequence A131140 A022114 
               A041099
%Y A049343 Adjacent sequences: A049340 A049341 A049342 this_sequence A049344 A049345 
               A049346
%K A049343 nonn,base,easy,nice
%O A049343 1,2
%A A049343 R. K. Guy (rkg(AT)cpsc.ucalgary.ca)

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