A107602 - OEIS

%I #2 Mar 30 2012 17:26:16

%S 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,12,22,32,24,52,26,

%T 72,28,92,3,31,32,33,34,35,36,37,38,39,40,14,42,34,44,54,46,74,48,94,

%U 50,51,52,53,54,55,56,57,58,59,60,16,62,36,64,56,66,76,68,96,70,71,72,73

%N In the natural numbers, swap digits in pairs (even-odd).

%C Differs from A000027 in a(21)=12.

%e 0 is even hence n = 21 => 12, n=101=>110, etc.

%Y Cf. A000027.

%K nonn,base

%O 1,2

%A _Zak Seidov_, May 17 2005