This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A052379 Number of integers from 1 to 10^(n+1)-1 that lack 0 and 1 as a digit. 11
 8, 72, 584, 4680, 37448, 299592, 2396744, 19173960, 153391688, 1227133512, 9817068104, 78536544840, 628292358728, 5026338869832, 40210710958664, 321685687669320, 2573485501354568, 20587884010836552, 164703072086692424 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..400 Index entries for linear recurrences with constant coefficients, signature (9,-8). FORMULA a(n) = (8^(n+2)-1)/7-1. G.f.: 8/((1-x)*(1-8*x)). - R. J. Mathar, Nov 19 2007 a(n) = 8*a(n-1) + 8. a(n) = sum(k=1..n, 8^k). - corrected by Michel Marcus, Sep 25 2014 Conjecture: a(n) = A023001(n+2)-1. - R. J. Mathar, May 18 2007. Comment from Vim Wenders, Mar 26 2008: The conjecture is true: the g.f. leads to the closed form a(n) = -8/7*(1^n) + 64/7*(8^n) = (-8 + 64*8^n)/7 = (-8 + 8^(n+2))/7 = (8^(n+2) - 1)/7 -1 = A023001(n+2)-1. a(0)=8, a(1)=72, a(n)=9*a(n-1)-8*a(n-2). - Harvey P. Dale, Sep 22 2013 EXAMPLE For n=1, the numbers from 1 to 99 which have 0 or 1 as a digit are the numbers 1 and 10, 20, 30, ..., 90 and 11, 12, ..., 18, 19 and 21, 31, ..., 91. So a(1) = 99 - 27 = 72. MAPLE A052379:=n->(8^(n+2)-1)/7-1: seq(A052379(n), n=0..20); # Wesley Ivan Hurt, Sep 26 2014 MATHEMATICA (8^(Range[0, 20]+2)-1)/7-1 (* or *) LinearRecurrence[{9, -8}, {8, 72}, 20] (* Harvey P. Dale, Sep 22 2013 *) PROG (MAGMA) [(8^(n+2)-1)/7-1: n in [0..20]]; // Vincenzo Librandi, Jul 04 2011 (PARI) a(n)=8^(n+2)\7 - 1 \\ Charles R Greathouse IV, Aug 25 2014 CROSSREFS Cf. A023001, A024101, A052386. Sequence in context: A270241 A054615 A111919 * A246940 A158798 A229249 Adjacent sequences:  A052376 A052377 A052378 * A052380 A052381 A052382 KEYWORD easy,nonn,base AUTHOR Odimar Fabeny, Mar 12 2000 EXTENSIONS More terms and revised description from James A. Sellers, Mar 13 2000 STATUS approved

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

Last modified August 24 22:41 EDT 2019. Contains 326314 sequences. (Running on oeis4.)