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%I #6 Jul 05 2016 02:48:10
%S 21,32,42,43,53,64,75,85,86,96,107,118,128,129,139,151,161,171,181,
%T 191,201,211,221,231,241,251,261,271,281,292,302,312,322,332,342,352,
%U 362,372,382,392,402,412,422,433,443,453,463,473,483,493,503,513,523,533
%N Numbers n with property that first digit of 7*n = last digit of n.
%H G. C. Greubel, <a href="/A168001/b168001.txt">Table of n, a(n) for n = 1..1000</a>
%e 7*21=147, 7*32=224, 7*42=294, 7*43=301, etc.
%t Reap[Do[If[IntegerDigits[n][[ -1]]==IntegerDigits[7*n][[1]],Sow[n]],{n,1000}]][[2,1]]
%t Select[Range[100], Last[IntegerDigits[#]] == First[IntegerDigits[7 #]] &] (* _G. C. Greubel_, Jul 03 2016 *)
%Y Cf. A167994, A167996, A167997, A167998, A168000.
%K base,nonn
%O 1,1
%A _Zak Seidov_, Nov 16 2009
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