Re: Numbers and their reversals

*To*: mathgroup at smc.vnet.net*Subject*: [mg53712] Re: Numbers and their reversals*From*: Bill Rowe <readnewsciv at earthlink.net>*Date*: Mon, 24 Jan 2005 03:37:37 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

On 1/23/05 at 2:02 AM, towtoo2002 at yahoo.com (F. omari) wrote: > >i want to investigate the following two equations: a * const = z >a_Reversed * const = z_Reversed where a, z, and their reversed form >and const are all positive integers ie such that: 2684 * 17 = 45628 >4862 * 17 = 82654 2986 * 91 = 271726 6892 * 91 = 627172 it happened >that many multipliers of 91 have such a property. while the >multipliers of 17 have only 5 cases in the interval of 1 to 3000 >the following code will investigate the multipliers of 17, to >investigate another number just replace 17. and you may increase >the interval of investigation. i am sure that my code is an old >fashion one, please any other ideas about a more functional code. >a = Table[i, {i, 1, 3000}]; zR = ""; aR = 0; z = ""; >Do[aR = ToExpression[StringReverse[ToString[a[[i]]]]]; > z = ToString[a[[i]]*17]; > zR = StringReverse[ToString[aR*17]]; > If[zR == z, Print[a[[i]]]], {i, 1, 3000}] The same result can be achieved using Select[Range@3000, IntegerDigits[17 #] == Reverse@IntegerDigits[17 FromDigits@Reverse@ IntegerDigits[#]]&] As an added bonus it runs a bit more than twice as fast OMM -- To reply via email subtract one hundred and four