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   Same Leading Digit
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   Author  Topic: Same Leading Digit  (Read 612 times)
ThudnBlunder
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Same Leading Digit  
« on: Sep 5th, 2004, 7:04am »
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When n = 0
2n = 1
5n = 1
(Same leading digit)
 
When n = 5
2n = 32
5n = 3125
(Same leading digit)
 
Can you find any more such examples?
 
« Last Edit: Sep 5th, 2004, 7:07am by ThudnBlunder » IP Logged

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Re: Same Leading Digit  
« Reply #1 on: Sep 5th, 2004, 9:30am »
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n=15.
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towr
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Re: Same Leading Digit  
« Reply #2 on: Sep 5th, 2004, 12:41pm »
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::
searching up to n = 200
 
n, 2n, 5n
 
0, 1, 1
 
5, 32, 3125
 
15, 32768, 30517578125
 
78, 302231454903657293676544, 3308722450212110699485634768279851414263248443603515625
 
88, 309485009821345068724781056, 32311742677852643549664402033982923967414535582065582275390625
 
98, 316912650057057350374175801344, 315544362088404722164691426113114491869282574043609201908111572265625
 
108, 324518553658426726783156020576256, 308148791101957736488956470813588370966096263714462111238390207290649414 0625
 
118, 332306998946228968225951765070086144, 300926553810505602039996553528894893521578382533654405506240436807274818 42041015625
 
181, 3064991081731777716716694054300618367237478244367204352, 326265223399926226335514705462827377785058212903448327387931822773486162 2298743113611448063426934140807134099304676055908203125
 
191, 3138550867693340381917894711603833208051177722232017256448, 318618382226490455405776079553542361118220911038523757214777170677232580 30261163218861797494403653718819668938522227108478546142578125
::
« Last Edit: Sep 5th, 2004, 12:44pm by towr » IP Logged

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Barukh
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Re: Same Leading Digit  
« Reply #3 on: Sep 6th, 2004, 4:25am »
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It is not difficult to see that there are infinitely many such numbers.
 
Using continued fractions one can find fairly big examples without actual search (but of course not all such numbers!).
 
Here're a few: 14369, 56408, 127185, 3053508, 22349997.
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