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A247187 Numbers containing nine distinct decimal digits (zero is not considered) and having the property that the digits 1 to 5 appear in the order but not the digits 1 to 6. 1

%I #11 Nov 24 2014 17:55:31

%S 123465789,123465798,123465879,123465897,123465978,123465987,

%T 123467589,123467598,123467859,123467895,123467958,123467985,

%U 123468579,123468597,123468759,123468795,123468957,123468975,123469578,123469587,123469758,123469785,123469857,123469875

%N Numbers containing nine distinct decimal digits (zero is not considered) and having the property that the digits 1 to 5 appear in the order but not the digits 1 to 6.

%C The sequence is finite and contains 2520 numbers.

%C To build a such number, first place the digits 1 to 5, and then insert the digit 6 anywhere but not after the digit 5, then the digits 7, 8 and 9. The order of the digits from 1 to 5 is imposed.

%C There are 5 ways to place the digits 6, 7 ways to place the digit 7, 8 ways to place the digit 8 and 9 ways to place the digit 9.

%C We obtain 5*7*8*9 = 2520 numbers.

%H Michel Lagneau, <a href="/A247187/b247187.txt">Table of n, a(n) for n = 1..2520</a>

%K nonn,base,fini,full,less

%O 1,1

%A _Michel Lagneau_, Nov 22 2014

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Last modified March 28 05:39 EDT 2024. Contains 371235 sequences. (Running on oeis4.)