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A167994 Numbers k with the property that the first digit of 2*k is the last digit of k. 10

%I

%S 12,24,25,37,49,51,61,71,81,91,102,112,122,132,142,153,163,173,183,

%T 193,204,214,224,234,244,255,265,275,285,295,306,316,326,336,346,357,

%U 367,377,387,397,408,418,428,438,448,459,469,479,489,499,501,511,521,531

%N Numbers k with the property that the first digit of 2*k is the last digit of k.

%H G. C. Greubel, <a href="/A167994/b167994.txt">Table of n, a(n) for n = 1..1000</a>

%e 2*12=24, 2*24=48, 2*25=50, 2*37=74.

%t Select[Range[600],Mod[#,10]==First[IntegerDigits[2#]]&] (* _Harvey P. Dale_, May 27 2014 *)

%K base,nonn

%O 1,1

%A _Zak Seidov_, Nov 16 2009

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Last modified October 21 15:46 EDT 2021. Contains 348155 sequences. (Running on oeis4.)