A168000 - OEIS

%I #8 Jul 05 2016 02:48:03

%S 21,31,42,53,63,74,85,95,106,116,117,127,138,148,159,171,181,191,201,

%T 211,221,231,241,251,261,271,281,291,301,311,321,331,342,352,362,372,

%U 382,392,402,412,422,432,442,452,462,472,482,492,503,513,523,533,543

%N Numbers n with property that first digit of 6*n = last digit of n.

%H G. C. Greubel, <a href="/A168000/b168000.txt">Table of n, a(n) for n = 1..1000</a>

%e 6*21=126, 6*31=186, 6*42=252, 6*53=318, etc.

%t Reap[Do[If[IntegerDigits[n][[ -1]]==IntegerDigits[6*n][[1]],Sow[n]],{n,1000}]][[2,1]]

%t Select[Range[600],Mod[#,10]==First[IntegerDigits[6#]]&] (* _Harvey P. Dale_, Jan 09 2014 *)

%Y Cf. A167994, A167996, A167997, A167998.

%K base,nonn

%O 1,1

%A _Zak Seidov_, Nov 16 2009