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 1-3 of 3 results.

A016186 Expansion of 1/((1-8*x)*(1-10*x)).

Original entry on oeis.org

1, 18, 244, 2952, 33616, 368928, 3951424, 41611392, 432891136, 4463129088, 45705032704, 465640261632, 4725122093056, 47800976744448, 482407813955584, 4859262511644672, 48874100093157376, 490992800745259008, 4927942405962072064, 49423539247696576512, 495388313981572612096, 4963106511852580896768
Offset: 0

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Author

Keywords

Comments

a(n) is the number of strings of n+1 decimal digits having an odd number of 0's. For 2 digits these are for example the 18 strings 01, 02, 03, ..., 09, 10, 20, 30, ..., 90. - Geoffrey Critzer, Jan 24 2011

Crossrefs

Programs

Formula

From R. J. Mathar, Sep 18 2008: (Start)
a(n) = 5*10^n - 4*8^n = A081203(n+1).
Binomial transform of A081035. (End)
From Geoffrey Critzer, Jan 24 2011: (Start)
a(n) = 8*a(n-1) + 10^(n-1).
E.g.f.: exp(9*x)*sinh(x) (with offset 1). (End)
A060531(n) = a(n) - 9*a(n-1). - R. J. Mathar_, Jan 27 2011
From Vincenzo Librandi, Feb 09 2011: (Start)
a(n) = 10*a(n-1) + 8^n, a(0)=1.
a(n) = 18*a(n-1) - 80*a(n-2), a(0)=1, a(1)=18. (End)
E.g.f.: exp(9*x)*( cosh(x) + 9*sinh(x) ). - G. C. Greubel, Nov 14 2024

Extensions

More terms added by G. C. Greubel, Nov 14 2024

A081034 7th binomial transform of the periodic sequence (1,8,1,1,8,1...).

Original entry on oeis.org

1, 15, 162, 1548, 13896, 120240, 1016352, 8457408, 69618816, 568707840, 4620206592, 37384915968, 301618907136, 2428188733440, 19516934725632, 156684026953728, 1256763510521856, 10073855853527040, 80709333444329472, 646385587251314688, 5175350216190590976, 41428394838605168640
Offset: 0

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Author

Paul Barry, Mar 03 2003

Keywords

Crossrefs

Programs

  • Mathematica
    RecurrenceTable[{a[0]==1,a[n]==8a[n-1]+7*6^(n-1)},a,{n,20}] (* or *) LinearRecurrence[{14,-48},{1,15},20] (* Harvey P. Dale, Jun 16 2013 *)

Formula

a(n) = 8*a(n-1) + 7*6^(n-1).
a(n) = (9/2)*8^n - (7/2)*6^n.
From Harvey P. Dale, Jun 16 2013: (Start)
a(0)=1, a(1)=15, a(n) = 14*a(n-1)-48*a(n-2).
G.f.: (x+1)/(48*x^2-14*x+1). (End)
E.g.f.: exp(6*x)*(9*exp(2*x) - 7)/2. - Stefano Spezia, Jul 23 2024

A081036 9th binomial transform of the periodic sequence (1,10,1,1,10,1...).

Original entry on oeis.org

1, 19, 262, 3196, 36568, 402544, 4320352, 45562816, 474502528, 4896020224, 50168161792, 511345294336, 5190762354688, 52526098837504, 530208790700032, 5341670325600256, 53733362604802048, 539866900838416384, 5418935206707331072, 54351481653658648576, 544811853229269188608
Offset: 0

Views

Author

Paul Barry, Mar 03 2003

Keywords

Crossrefs

Programs

  • Magma
    [(11/2)*10^n-(9/2)*8^n: n in [0..25]]; // Vincenzo Librandi, Aug 06 2013
  • Mathematica
    CoefficientList[Series[(1 + x)/((1 - 8 x) (1 - 10 x)), {x, 0, 30}], x] (* Vincenzo Librandi, Aug 06 2013 *)
    LinearRecurrence[{18,-80},{1,19},20] (* Harvey P. Dale, Aug 16 2014 *)

Formula

a(n) = 10*a(n-1) + 9*8^(n-1).
a(n) = (11/2)*10^n - (9/2)*8^n.
G.f.: (1+x)/((1-8*x)*(1-10*x)). - Vincenzo Librandi, Aug 06 2013
a(0)=1, a(1)=19, a(n)=18*a(n-1)-80*a(n-2). - Harvey P. Dale, Aug 16 2014
E.g.f.: exp(8*x)*(11*exp(2*x) - 9)/2. - Stefano Spezia, Jul 23 2024

Extensions

Corrected by T. D. Noe, Nov 07 2006
Showing 1-3 of 3 results.