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Search: id:A131760
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%I A131760
%S A131760 1,4,9,121,484,676,2178,8712,10000,10201,12321,14641,40000,40804,44944,
%T A131760 69696,90000,94249,698896,1002001,1210000,1234321,4008004,4840000,
%U A131760 5221225,6760000,6948496,21780000,87120000,100000000,100020001
%N A131760 Numbers n such that n multiplied by its reverse yields a fourth power.
%C A131760 This sequence contains palindromic squares and palindromic squares with 
               trailing zeros. Are 2178 and 8721 the only non-palindromic reversible 
               pair in this sequence without trailing zeros?
%e A131760 2178 = 2*9*121 and 8712 = 8*9*121, 2718*8712 = (2*3*11)^4.
%t A131760 Select[Range[1000000], IntegerQ[(#*FromDigits[Reverse[IntegerDigits[ 
               # ]]])^(1/4)] &]
%Y A131760 Cf. A002779 = Palindromic squares.
%Y A131760 Sequence in context: A115676 A115667 A158642 this_sequence A002779 A028817 
               A057136
%Y A131760 Adjacent sequences: A131757 A131758 A131759 this_sequence A131761 A131762 
               A131763
%K A131760 nonn,base
%O A131760 1,2
%A A131760 Tanya Khovanova (tanyakh(AT)yahoo.com), Sep 17 2007
%E A131760 a(20)-a(31) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Oct 
               27 2008

    
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Last modified December 10 12:37 EST 2009. Contains 170569 sequences.


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