login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A125945 a(n) is the number of nonnegative integers k less than 10^n such that the decimal representation of k lacks at least one of digits 1,2, at least one of digits 3,4 and at least one of digits 5,6,7,8,9. 19

%I #13 Sep 24 2015 11:41:23

%S 10,96,892,8076,71500,619236,5241652,43355436,350740540,2780210676,

%T 21641505412,165814383996,1253254845580,9362782430916,69259450905172,

%U 508062802935756,3700662365318620,26794126632247956,193018363703408932,1384505203965202716

%N a(n) is the number of nonnegative integers k less than 10^n such that the decimal representation of k lacks at least one of digits 1,2, at least one of digits 3,4 and at least one of digits 5,6,7,8,9.

%H Colin Barker, <a href="/A125945/b125945.txt">Table of n, a(n) for n = 1..1000</a>

%H Milan Janjic, <a href="http://www.pmfbl.org/janjic/">Enumerative Formulas for Some Functions on Finite Sets</a>

%H <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (28,-322,1960,-6769,13132,-13068,5040).

%F a(n) = 20*7^n-60*6^n+85*5^n-70*4^n+34*3^n-9*2^n+1.

%F G.f.: -2*x*(2520*x^6 -6054*x^5 +6063*x^4 -2794*x^3 +712*x^2 -92*x +5) / ((x -1)*(2*x -1)*(3*x -1)*(4*x -1)*(5*x -1)*(6*x -1)*(7*x -1)). - _Colin Barker_, Feb 23 2015

%p f:=n->20*7^n-60*6^n+85*5^n-70*4^n+34*3^n-9*2^n+1;

%o (PARI) a(n)=20*7^n-60*6^n+85*5^n-70*4^n+34*3^n-9*2^n+1 \\ _Charles R Greathouse IV_, Sep 24 2015

%Y Cf. A125630.

%K nonn,base,easy

%O 1,1

%A Aleksandar M. Janjic and _Milan Janjic_, Feb 04 2007

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 29 01:36 EDT 2024. Contains 371264 sequences. (Running on oeis4.)