cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-2 of 2 results.

A165154 a(n) = 100*a(n-1) + (-9)^(n-1) for n>0, a(0)=0.

Original entry on oeis.org

0, 1, 91, 9181, 917371, 91743661, 9174307051, 917431236541, 91743118871131, 9174311930159821, 917431192628561611, 91743119266342945501, 9174311926602913490491, 917431192660573778585581, 91743119266054835992729771, 9174311926605506476065432061
Offset: 0

Views

Author

Mark Dols, Sep 05 2009

Keywords

Crossrefs

Programs

  • Magma
    [(1/109)*(100^n-(-9)^n): n in [0..20]]; // Vincenzo Librandi, Jun 10 2011
    
  • Mathematica
    LinearRecurrence[{91,900}, {0,1}, 40] (* G. C. Greubel, Feb 09 2023 *)
  • PARI
    Vec(x/((1+9*x)*(1-100*x)) + O(x^20)) \\ Colin Barker, Oct 02 2015
    
  • SageMath
    [(100^n-(-9)^n)/109 for n in range(41)] # G. C. Greubel, Feb 09 2023

Formula

From Colin Barker, Oct 02 2015: (Start)
a(n) = 91*a(n-1) + 900*a(n-2) for n>1, a(0)=0.
G.f.: x/((1+9*x)*(1-100*x)). (End)
E.g.f.: (1/109)*(exp(100*x) - exp(-9*x)). - G. C. Greubel, Feb 09 2023

Extensions

a(0) prepended by Joerg Arndt, Oct 02 2015

A172163 a(n) = ( A165155(n) - A165154(n) )/2.

Original entry on oeis.org

0, 0, 10, 1020, 103030, 10307040, 1030814050, 103082025060, 10308214641070, 1030821549763080, 103082156348992090, 10308215646124529100, 1030821564770799275110, 103082156478507926931120, 10308215647869324982098130, 1030821564787110934730377140
Offset: 0

Views

Author

Mark Dols, Jan 27 2010

Keywords

Crossrefs

Programs

  • Mathematica
    Table[10^(2 n + 1)/9701 - 11^n/178 + (-9)^n/218, {n, 0, 20}] (* Bruno Berselli, Oct 02 2015 *)
    LinearRecurrence[{102,-101,-9900},{0,0,10},20] (* Harvey P. Dale, Aug 17 2021 *)
  • PARI
    concat([0,0], Vec(10*x^2/((9*x+1)*(11*x-1)*(100*x-1)) + O(x^30))) \\ Colin Barker, Oct 02 2015
    
  • SageMath
    [(89*(-9)^n + 2*10^(2*n+1) - 109*11^n)/19402 for n in (0..50)] # G. C. Greubel, Apr 24 2022

Formula

a(n) = 10^(2*n+1)/9701 - 11^n/178 + (-9)^n/218. [Bruno Berselli, Oct 02 2015]
From Colin Barker, Oct 02 2015: (Start)
a(n) = 102*a(n-1) - 101*a(n-2) - 9900*a(n-3) for n>2.
G.f.: 10*x^2 / ((1+9*x)*(1-11*x)*(1-100*x)).
(End)

Extensions

a(0)=0 and more terms added by Bruno Berselli, Oct 02 2015
Showing 1-2 of 2 results.