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 1-10 of 10 results.

A145729 Partial sums of A052379.

Original entry on oeis.org

0, 8, 80, 664, 5344, 42792, 342384, 2739128, 21913088, 175304776, 1402438288, 11219506392, 89756051232, 718048409960, 5744387279792, 45955098238456, 367640785907776, 2941126287262344, 23529010298098896, 188232082384791320
Offset: 0

Views

Author

Keywords

Crossrefs

Cf. A052379.

Programs

  • Magma
    [8*(8^(n+1)-7*n-8)/49 : n in [0..20]]; // Vincenzo Librandi, Jul 04 2011
    
  • Mathematica
    lst={};s=0;Do[s+=(s+=(s+=(s+=n)));AppendTo[lst,s],{n,0,5!}];lst
  • PARI
    concat(0, Vec(-8*x/((x-1)^2*(8*x-1)) + O(x^100))) \\ Colin Barker, Oct 27 2014

Formula

a(n) = sum_{i=0..n-1} A052379(i).
a(n) = 8*(8^(n+1)-7*n-8)/49 = 8*A014831(n) = 2*A145730(n). - R. J. Mathar, Oct 21 2008
a(n) = 10*a(n-1)-17*a(n-2)+8*a(n-3). G.f.: -8*x / ((x-1)^2*(8*x-1)). - Colin Barker, Oct 27 2014

Extensions

Edited by R. J. Mathar, Oct 21 2008

A024101 a(n) = 9^n-1.

Original entry on oeis.org

0, 8, 80, 728, 6560, 59048, 531440, 4782968, 43046720, 387420488, 3486784400, 31381059608, 282429536480, 2541865828328, 22876792454960, 205891132094648, 1853020188851840, 16677181699666568, 150094635296999120
Offset: 0

Views

Author

Keywords

Comments

Number of integers from 0 to 10^(n+1)-1 that lack any particular digit other than 0. - Robert G. Wilson v, Apr 14 2003
These are the numbers 888...8 in base 9. - Zerinvary Lajos, Nov 21 2007

Crossrefs

Programs

Formula

G.f.: 1/(1-9*x)-1/(1-x). - Mohammad K. Azarian, Jan 14 2009
E.g.f.: e^(9*x)-e^x. - Mohammad K. Azarian, Jan 14 2009
a(n) = A024023(n)*A034472(n). - Reinhard Zumkeller, Feb 14 2009
a(n) = 9*a(n-1)+8 for n>0, a(0)=0. - Vincenzo Librandi, Nov 19 2010
a(0)=0, a(1)=8; for n>1, a(n) = 10*a(n-1)-9*a(n-2). - Harvey P. Dale, Apr 14 2015
a(n) = Sum_{i=1..n} 8^i*binomial(n,n-i) for n>0, a(0)=0. - Bruno Berselli, Nov 11 2015
a(n) = A001019(n) - 1. - Sean A. Irvine, Jun 19 2019
Sum_{n>=1} 1/a(n) = A248726. - Amiram Eldar, Nov 13 2020

A228275 A(n,k) = Sum_{i=1..k} n^i; square array A(n,k), n>=0, k>=0, read by antidiagonals.

Original entry on oeis.org

0, 0, 0, 0, 1, 0, 0, 2, 2, 0, 0, 3, 6, 3, 0, 0, 4, 14, 12, 4, 0, 0, 5, 30, 39, 20, 5, 0, 0, 6, 62, 120, 84, 30, 6, 0, 0, 7, 126, 363, 340, 155, 42, 7, 0, 0, 8, 254, 1092, 1364, 780, 258, 56, 8, 0, 0, 9, 510, 3279, 5460, 3905, 1554, 399, 72, 9, 0
Offset: 0

Views

Author

Alois P. Heinz, Aug 19 2013

Keywords

Comments

A(n,k) is the total sum of lengths of longest ending contiguous subsequences with the same value over all s in {1,...,n}^k:
A(4,1) = 4 = 1+1+1+1: [1], [2], [3], [4].
A(1,4) = 4: [1,1,1,1].
A(3,2) = 12 = 2+1+1+1+2+1+1+1+2: [1,1], [1,2], [1,3], [2,1], [2,2], [2,3], [3,1], [3,2], [3,3].
A(2,3) = 14 = 3+1+1+2+2+1+1+3: [1,1,1], [1,1,2], [1,2,1], [1,2,2], [2,1,1], [2,1,2], [2,2,1], [2,2,2].

Examples

			Square array A(n,k) begins:
  0, 0,  0,   0,    0,     0,      0,      0, ...
  0, 1,  2,   3,    4,     5,      6,      7, ...
  0, 2,  6,  14,   30,    62,    126,    254, ...
  0, 3, 12,  39,  120,   363,   1092,   3279, ...
  0, 4, 20,  84,  340,  1364,   5460,  21844, ...
  0, 5, 30, 155,  780,  3905,  19530,  97655, ...
  0, 6, 42, 258, 1554,  9330,  55986, 335922, ...
  0, 7, 56, 399, 2800, 19607, 137256, 960799, ...
		

Crossrefs

Rows n=0-11 give: A000004, A001477, A000918(k+1), A029858(k+1), A080674, A104891, A105281, A104896, A052379(k-1), A052386, A105279, A105280.
Main diagonal gives A031972.
Lower diagonal gives A226238.
Cf. A228250.

Programs

  • Maple
    A:= (n, k)-> `if`(n=1, k, (n/(n-1))*(n^k-1)):
    seq(seq(A(n, d-n), n=0..d), d=0..12);
  • Mathematica
    a[0, 0] = 0; a[1, k_] := k; a[n_, k_] := n*(n^k-1)/(n-1); Table[a[n-k, k], {n, 0, 12}, {k, n, 0, -1}] // Flatten (* Jean-François Alcover, Dec 16 2013 *)

Formula

A(1,k) = k, else A(n,k) = n/(n-1)*(n^k-1).
A(n,k) = Sum_{i=1..k} n^i.
A(n,k) = Sum_{i=1..k+1} binomial(k+1,i)*A(n-i,k)*(-1)^(i+1) for n>k, given values A(0,k), A(1,k),..., A(k,k). - Yosu Yurramendi, Sep 03 2013

A052386 Number of integers from 1 to 10^n-1 that lack 0 as a digit.

Original entry on oeis.org

0, 9, 90, 819, 7380, 66429, 597870, 5380839, 48427560, 435848049, 3922632450, 35303692059, 317733228540, 2859599056869, 25736391511830, 231627523606479, 2084647712458320, 18761829412124889, 168856464709124010, 1519708182382116099, 13677373641439044900
Offset: 0

Views

Author

Odimar Fabeny, Mar 10 2000

Keywords

Examples

			For n=2, the numbers from 1 to 99 which *have* 0 as a digit are the 9 numbers 10, 20, 30, ..., 90. So a(1) = 99 - 9 = 90.
		

Crossrefs

Row n=9 of A228275.

Programs

Formula

a(n) = 9*a(n-1) + 9.
a(n) = 9*(9^n-1)/8 = sum_{j=1..n} 9^j = a(n-1)+9^n = 9*A002452(n) = A002452(n+1)-1; write A000918(n+1) in base 2 and read as if written in base 9. - Henry Bottomley, Aug 30 2001
a(n) = 10*a(n-1)-9*a(n-2). G.f.: 9*x / ((x-1)*(9*x-1)). - Colin Barker, Sep 26 2013

Extensions

More terms and revised description from James Sellers, Mar 13 2000
More terms and revised description from Robert G. Wilson v, Apr 14 2003
More terms from Colin Barker, Sep 26 2013

A105279 a(0)=0; a(n) = 10*a(n-1) + 10.

Original entry on oeis.org

0, 10, 110, 1110, 11110, 111110, 1111110, 11111110, 111111110, 1111111110, 11111111110, 111111111110, 1111111111110, 11111111111110, 111111111111110, 1111111111111110, 11111111111111110, 111111111111111110, 1111111111111111110, 11111111111111111110, 111111111111111111110
Offset: 0

Views

Author

Alexandre Wajnberg, Apr 25 2005

Keywords

Comments

a(n) is the smallest even number with digits in {0,1} having digit sum n; in other words, the base 10 reading of the binary string of A000918(n). Cf. A069532. - Jason Kimberley, Nov 02 2011
Also, except for a(0), the binary representation of the diagonal from the corner to the origin of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 645", based on the 5-celled von Neumann neighborhood, initialized with a single black (ON) cell at stage zero. - Robert Price, Jul 19 2017

References

  • S. Wolfram, A New Kind of Science, Wolfram Media, 2002; p. 170.

Crossrefs

Row n=10 of A228275.
Partial sums of A178500.

Programs

  • Haskell
    a105279 n = a105279_list !! n
    a105279_list = iterate ((* 10) . (+ 1)) 0
    -- Reinhard Zumkeller, Feb 05 2012
  • Magma
    [-10/9+(10/9)*10^n: n in [0..20]]; // Vincenzo Librandi, Jul 04 2011
    
  • Mathematica
    NestList[10*(# + 1) &, 0, 25] (* Paolo Xausa, Jul 17 2024 *)

Formula

a(n) = (10/9)*(10^n - 1), with n>=0.
a(n) = Sum_{k=1..n} 10^k.
Repunits times 10: a(n) = 10 * A002275(n). - Reinhard Zumkeller, Feb 05 2012
From Stefano Spezia, Sep 15 2023: (Start)
O.g.f.: 10*x/((1 - x)*(1 - 10*x)).
E.g.f.: 10*exp(x)*(exp(9*x) - 1)/9. (End)
From Elmo R. Oliveira, Jun 18 2025: (Start)
a(n) = 11*a(n-1) - 10*a(n-2).
a(n) = A124166(n)/10.
a(n) = A161770(n)/100 for n >= 1. (End)

A104891 a(0) = 0; a(n) = 5*a(n-1) + 5.

Original entry on oeis.org

0, 5, 30, 155, 780, 3905, 19530, 97655, 488280, 2441405, 12207030, 61035155, 305175780, 1525878905, 7629394530, 38146972655, 190734863280, 953674316405, 4768371582030, 23841857910155, 119209289550780, 596046447753905, 2980232238769530, 14901161193847655
Offset: 0

Views

Author

Alexandre Wajnberg, Apr 24 2005

Keywords

Comments

Number of integers from 0 to (10^n)-1 that lack 0, 1, 2, 3 and 4 as a digit.
Number of monic irreducible polynomials of degree 1 in GF(5)[x1,...,xn]. - Max Alekseyev, Jan 23 2006

Examples

			a(3) = 5*a(2) + 5 = 5*30 + 5 = 155.
		

Crossrefs

Programs

  • Magma
    [5*(5^n -1)/4: n in [0..30]]; // G. C. Greubel, Jun 15 2021
    
  • Maple
    a:=n->add(5^j,j=1..n): seq(a(n),n=0..30); # Zerinvary Lajos, Jun 27 2007
  • Mathematica
    RecurrenceTable[{a[n]==5*a[n-1]+5, a[0]==0}, a, {n, 0, 30}] (* Vaclav Kotesovec, Jul 25 2014 *)
    NestList[5#+5&,0,30] (* Harvey P. Dale, Oct 04 2019 *)
  • PARI
    concat(0, Vec(5*x/((x-1)*(5*x-1)) + O(x^30))) \\ Colin Barker, Jul 25 2014
    
  • Sage
    [5*(5^n -1)/4 for n in (0..30)] # G. C. Greubel, Jun 15 2021

Formula

a(n) = 5*(5^n - 1)/4. - Max Alekseyev, Jan 23 2006
a(n) = a(n-1) + 5^n with a(0)=0. - Vincenzo Librandi, Nov 13 2010
From Colin Barker, Jul 25 2014: (Start)
a(n) = 6*a(n-1) - 5*a(n-2).
G.f.: 5*x / ((1-x)*(1-5*x)). (End)
E.g.f.: (5/4)*(exp(5*x) - exp(x)). - G. C. Greubel, Jun 15 2021

A104896 a(0) = 0; a(n) = 7*a(n-1) + 7.

Original entry on oeis.org

0, 7, 56, 399, 2800, 19607, 137256, 960799, 6725600, 47079207, 329554456, 2306881199, 16148168400, 113037178807, 791260251656, 5538821761599, 38771752331200, 271402266318407, 1899815864228856, 13298711049601999, 93090977347214000, 651636841430498007
Offset: 0

Views

Author

Alexandre Wajnberg, Apr 24 2005

Keywords

Comments

Conjecture: this is also the number of integers from 0 to 10^n - 1 that lack 0, 1 and 2 as a digit.
Number of monic irreducible polynomials of degree 1 in GF(7)[x1,...,xn]. - Max Alekseyev, Jan 23 2006

Crossrefs

Programs

  • Magma
    [(7/6)*(7^n -1): n in [0..30]]; // G. C. Greubel, Jun 09 2021
    
  • Maple
    a:=n->sum (7^j,j=1..n): seq(a(n), n=0..30); # Zerinvary Lajos, Oct 03 2007
  • Mathematica
    RecurrenceTable[{a[n]==7*a[n-1]+7,a[0]==0},a,{n,0,30}] (* Vaclav Kotesovec, Jul 25 2014 *)
  • PARI
    concat(0, Vec(7*x/((x-1)*(7*x-1)) + O(x^30))) \\ Colin Barker, Jul 25 2014
    
  • Sage
    [(7/6)*(7^n -1) for n in (0..30)] # G. C. Greubel, Jun 09 2021

Formula

a(n) = (7^(n+1) - 7) / 6. - Max Alekseyev, Jan 23 2006
a(n) = a(n-1) + 7^n with a(0)=0. - Vincenzo Librandi, Nov 13 2010
From Colin Barker, Jul 25 2014: (Start)
a(n) = 8*a(n-1) - 7*a(n-2).
G.f.: 7*x / ((x-1)*(7*x-1)). (End)
E.g.f.: (7/6)*(exp(7*x) - exp(x)). - G. C. Greubel, Jun 09 2021

A105281 a(0)=0; a(n) = 6*a(n-1) + 6.

Original entry on oeis.org

0, 6, 42, 258, 1554, 9330, 55986, 335922, 2015538, 12093234, 72559410, 435356466, 2612138802, 15672832818, 94036996914, 564221981490, 3385331888946, 20311991333682, 121871948002098, 731231688012594, 4387390128075570, 26324340768453426, 157946044610720562
Offset: 0

Views

Author

Alexandre Wajnberg, Apr 25 2005

Keywords

Comments

Number of integers from 0 to (10^n) - 1 that lack 0, 1, 2 and 3 as a digit.
a(n) is the expected number of tosses of a single die needed to obtain for the first time a string of n consecutive 6's. - Jean M. Morales, Aug 04 2012

Crossrefs

Programs

  • Maple
    a:=n->add(6^j,j=1..n): seq(a(n),n=0..30); # Zerinvary Lajos, Oct 03 2007
  • Mathematica
    NestList[6#+6&,0,30] (* Harvey P. Dale, Jul 24 2012 *)
  • PARI
    a(n)=if(n<0,0, (6^n-1)*6/5)

Formula

a(n) = 6^n + a(n-1) (with a(0)=0). - Vincenzo Librandi, Nov 13 2010
From Colin Barker, Jan 28 2013: (Start)
a(n) = 7*a(n-1) - 6*a(n-2).
G.f.: 6*x/((x-1)*(6*x-1)). (End)
From Elmo R. Oliveira, Mar 16 2025: (Start)
E.g.f.: 6*exp(x)*(exp(5*x) - 1)/5.
a(n) = 6*(6^n - 1)/5.
a(n) = 6*A003464(n). (End)

Extensions

More terms from Harvey P. Dale, Jul 24 2012

A105280 a(0)=0; a(n) = 11*a(n-1) + 11.

Original entry on oeis.org

0, 11, 132, 1463, 16104, 177155, 1948716, 21435887, 235794768, 2593742459, 28531167060, 313842837671, 3452271214392, 37974983358323, 417724816941564, 4594972986357215, 50544702849929376, 555991731349223147, 6115909044841454628, 67274999493256000919, 740024994425816010120
Offset: 0

Views

Author

Alexandre Wajnberg, Apr 25 2005

Keywords

Crossrefs

Programs

  • Maple
    a:=n-> add(11^j,j=1..n): seq(a(n),n=0..12); # Zerinvary Lajos, Oct 03 2007
  • Mathematica
    NestList[11#+11&,0,20] (* or *) LinearRecurrence[{12,-11},{0,11},20] (* Harvey P. Dale, Dec 02 2023 *)

Formula

a(n) = 11^n + a(n-1) (with a(0)=0). - Vincenzo Librandi, Nov 13 2010
From Elmo R. Oliveira, May 24 2025: (Start)
G.f.: 11*x/((x-1)*(11*x-1)).
E.g.f.: 11*exp(x)*(exp(10*x) - 1)/10.
a(n) = 11*(11^n - 1)/10.
a(n) = 12*a(n-1) - 11*a(n-2).
a(n) = A016123(n) - 1. (End)

Extensions

Corrected by T. D. Noe, Nov 07 2006

A247841 a(n) = Sum_{k=2..n} 8^k.

Original entry on oeis.org

0, 64, 576, 4672, 37440, 299584, 2396736, 19173952, 153391680, 1227133504, 9817068096, 78536544832, 628292358720, 5026338869824, 40210710958656, 321685687669312, 2573485501354560, 20587884010836544, 164703072086692416, 1317624576693539392
Offset: 1

Views

Author

Vincenzo Librandi, Sep 25 2014

Keywords

Crossrefs

Cf. similar sequences listed in A247817.
Cf. A052379.

Programs

  • Magma
    [0] cat [&+[8^k: k in [2..n]]: n in [2..30]];
    
  • Magma
    [(8^(n+1)-64)/7: n in [1..30]];
  • Mathematica
    RecurrenceTable[{a[1] == 0, a[n] == a[n-1] + 8^n}, a, {n, 30}] (* or *) CoefficientList[Series[64 x / ((1 - x) (1 - 8 x)), {x, 0, 30}], x]
    LinearRecurrence[{9,-8},{0,64},30] (* Harvey P. Dale, May 01 2018 *)

Formula

G.f.: 64*x^2/((1-x)*(1-8*x)).
a(n) = a(n-1) + 8^n.
a(n) = (8^(n+1) - 64)/7.
a(n) = 9*a(n-1) - 8*a(n-2).
a(n) = A052379(n) - 8. - Michel Marcus, Sep 25 2014
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