A110725 - OEIS

%I #12 Nov 10 2017 13:33:24

%S 0,2,4,6,8,10,12,14,16,18,101,202,303,404,505,606,707,808,909,1010,

%T 202,303,404,505,606,707,808,909,1010,1111,303,404,505,606,707,808,

%U 909,1010,1111,1212,404,505,606,707,808,909,1010,1111,1212,1313,505

%N [{n concatenate R(n)} + {R(n) concatenate n}]/11, where R(n) = digit reversal of n.

%H G. C. Greubel, <a href="/A110725/b110725.txt">Table of n, a(n) for n = 0..1000</a>

%F A110724(n)/11.

%F When n has one digit, a(n)=2*n. When n has two digits, a(n)= 101*x + 101*y. (Here x,y are the digits of n.). - _Keith Schneider_, Jun 16 2007

%e a(12) = {1221 + 2112}/11 = 303. a(68) = {6886 + 8668}/11 = 1414.

%t Table[(FromDigits[Join[IntegerDigits[n], Reverse[IntegerDigits[n]]]] + FromDigits[Join[Reverse[IntegerDigits[n]], IntegerDigits[n]]])/11, {n, 0, 50}] (* _Stefan Steinerberger_, Jun 17 2007 *)

%t cr[n_]:=Module[{r=IntegerReverse[n]},(n*10^IntegerLength[n]+r+ r*10^ IntegerLength[ n]+n)/11]; Array[cr,60,0] (* _Harvey P. Dale_, Nov 10 2017 *)

%Y Cf. A110722, A110723, A110724.

%K base,nonn,less,easy

%O 0,2

%A _Amarnath Murthy_, Aug 09 2005

%E Corrected and extended by _Stefan Steinerberger_, Jun 17 2007