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.

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A218733 a(n) = (30^n - 1)/29.

Original entry on oeis.org

0, 1, 31, 931, 27931, 837931, 25137931, 754137931, 22624137931, 678724137931, 20361724137931, 610851724137931, 18325551724137931, 549766551724137931, 16492996551724137931, 494789896551724137931, 14843696896551724137931, 445310906896551724137931, 13359327206896551724137931
Offset: 0

Views

Author

M. F. Hasler, Nov 04 2012

Keywords

Comments

Partial sums of powers of 30 (A009974).

Crossrefs

Programs

Formula

a(n) = floor(30^n/29).
From Vincenzo Librandi, Nov 07 2012: (Start)
G.f.: x/((1-x)*(1-30*x)).
a(n) = 31*a(n-1) - 30*a(n-2). (End)
E.g.f.: exp(x)*(exp(29*x) - 1)/29. - Elmo R. Oliveira, Aug 29 2024

A218740 a(n) = (37^n - 1)/36.

Original entry on oeis.org

0, 1, 38, 1407, 52060, 1926221, 71270178, 2636996587, 97568873720, 3610048327641, 133571788122718, 4942156160540567, 182859777940000980, 6765811783780036261, 250335035999861341658, 9262396331994869641347, 342708664283810176729840, 12680220578500976539004081
Offset: 0

Views

Author

M. F. Hasler, Nov 04 2012

Keywords

Comments

Partial sums of powers of 37 (A009981).

Crossrefs

Programs

Formula

From Vincenzo Librandi, Nov 07 2012: (Start)
G.f.: x/((1 - x)*(1 - 37*x)).
a(n) = 38*a(n-1) - 37*a(n-2).
a(n) = floor(37^n/36). (End)
E.g.f.: exp(x)*(exp(36*x) - 1)/36. - Stefano Spezia, Mar 28 2023

A218744 a(n) = (41^n - 1)/40.

Original entry on oeis.org

0, 1, 42, 1723, 70644, 2896405, 118752606, 4868856847, 199623130728, 8184548359849, 335566482753810, 13758225792906211, 564087257509154652, 23127577557875340733, 948230679872888970054, 38877457874788447772215, 1593975772866326358660816, 65353006687519380705093457
Offset: 0

Views

Author

M. F. Hasler, Nov 04 2012

Keywords

Comments

Partial sums of powers of 41 (A009985).

Crossrefs

Programs

Formula

a(n) = floor(41^n/40).
G.f.: x/((1-x)*(1-41*x)). - Vincenzo Librandi, Nov 07 2012
a(n) = 42*a(n-1) - 41*a(n-2). - Vincenzo Librandi, Nov 07 2012
E.g.f.: exp(21*x)*sinh(20*x)/20. - Elmo R. Oliveira, Aug 27 2024

A218746 a(n) = (43^n - 1)/42.

Original entry on oeis.org

0, 1, 44, 1893, 81400, 3500201, 150508644, 6471871693, 278290482800, 11966490760401, 514559102697244, 22126041415981493, 951419780887204200, 40911050578149780601, 1759175174860440565844, 75644532518998944331293, 3252714898316954606245600, 139866740627629048068560801
Offset: 0

Views

Author

M. F. Hasler, Nov 04 2012

Keywords

Comments

Partial sums of powers of 43 (A009987).
0 followed by the binomial transform of A170762. - R. J. Mathar, Jul 18 2015

Crossrefs

Programs

Formula

G.f.: x/((1-x)*(1-43*x)). - Vincenzo Librandi, Nov 07 2012
a(n) = 44*a(n-1) - 43*a(n-2). - Vincenzo Librandi, Nov 07 2012
a(n) = floor(43^n/42). - Vincenzo Librandi, Nov 07 2012
E.g.f.: exp(22*x)*sinh(21*x)/21. - Elmo R. Oliveira, Aug 27 2024

A098704 Decimal form of the binary numbers 10, 100010, 1000100010, 10001000100010, 100010001000100010,...

Original entry on oeis.org

2, 34, 546, 8738, 139810, 2236962, 35791394, 572662306, 9162596898, 146601550370, 2345624805922, 37529996894754, 600479950316066, 9607679205057058, 153722867280912930, 2459565876494606882
Offset: 2

Views

Author

Simone Severini, Oct 26 2004

Keywords

Comments

Decimal form of the hexadecimal numbers 2, 22, 222, 2222, 22222, 222222, ...; e.g., 2*16^0 + 2*16^1 = 2 + 32 = 34. - Zerinvary Lajos, Feb 01 2007
For n>0: A131852(a(n+1))=n and ABS(A131852(m))A131865(n-2). - Reinhard Zumkeller, Jul 22 2007
Third quadrisection of A115451. - Klaus Purath, Mar 14 2021

Programs

  • Mathematica
    s=0;lst={};Do[s+=2^n;AppendTo[lst, s], {n, 1, 2*5!, 4}];lst (* Vladimir Joseph Stephan Orlovsky, Nov 07 2008 *)
    FromDigits[#,2]&/@Table[Join[PadRight[{},4n,{1,0,0,0}],{1,0}],{n,0,20}] (* Harvey P. Dale, Apr 06 2020 *)
  • PARI
    for(n=0,20,print(2*sum(k=0,n,2^(4*k))))
    for(k=0,20,print(2*(1-16^(k+1))/-15))

Formula

lim_{n -> infinity} a(n)/a(n-k) = 2^(4*(n-k)).
2*Sum_{k=0..n} 16^k = 2*(16^(n+1) - 1)/15.
From Klaus Purath, Mar 14 2021: (Start)
a(n) = (2^(4*n-3)-2)/15.
a(n) = 17*a(n-1) - 16*a(n-2).
a(n) = 16*a(n-1) + 2.
a(n) = 2*16^(n-2) + a(n-1).
a(n) = 2*A131865(n-2). (End)

Extensions

More terms from Ray Chandler, Nov 02 2004
More terms from Vladimir Joseph Stephan Orlovsky, Nov 07 2008

A108020 a(n) is the number whose binary representation is the concatenation of n strings of the four digits "1100".

Original entry on oeis.org

0, 12, 204, 3276, 52428, 838860, 13421772, 214748364, 3435973836, 54975581388, 879609302220, 14073748835532, 225179981368524, 3602879701896396, 57646075230342348, 922337203685477580, 14757395258967641292, 236118324143482260684, 3777893186295716170956
Offset: 0

Views

Author

Alexandre Wajnberg, May 31 2005

Keywords

Comments

Numbers whose base-16 representation consists entirely of 12's; 12 times base-16 repunits. - Franklin T. Adams-Watters, Mar 29 2006

Examples

			a(3) = 3276 because 3276 written in base 2 is the digit string "1100" written three times: 110011001100.
		

Crossrefs

Programs

  • Mathematica
    Table[ FromDigits[ Flatten[ Table[{1, 1, 0, 0}, {i, n}]], 2], {n, 0, 16}] (* Robert G. Wilson v, Jun 01 2005 *)
    Table[FromDigits[PadRight[{},4n,{1,1,0,0}],2],{n,0,20}] (* Harvey P. Dale, Aug 12 2012 *)
  • PARI
    concat(0, Vec(12*x/((1-x)*(1-16*x)) + O(x^100))) \\ Colin Barker, Dec 06 2015
    
  • PARI
    a(n)=12*(16^n - 1)/15 \\ Charles R Greathouse IV, Nov 01 2022

Formula

a(n) = 12*(16^n - 1)/15. - Franklin T. Adams-Watters, Mar 29 2006
From Colin Barker, Dec 06 2015: (Start)
a(n) = 17*a(n-1) - 16*a(n-2) for n > 1.
G.f.: 12*x / ((1-x)*(1-16*x)).
(End)
a(n) = 4*A182512(n). - Jamie Simpson, Oct 25 2022
a(n) = 12*A131865(n-1) for n>0. - Hugo Pfoertner, Nov 01 2022

Extensions

More terms from Robert G. Wilson v, Jun 01 2005

A141060 Fourth quadrisection of Jacobsthal numbers A001045: a(n)=16a(n-1)-5.

Original entry on oeis.org

3, 43, 683, 10923, 174763, 2796203, 44739243, 715827883, 11453246123, 183251937963, 2932031007403, 46912496118443, 750599937895083, 12009599006321323, 192153584101141163, 3074457345618258603, 49191317529892137643
Offset: 0

Views

Author

Paul Curtz, Jul 30 2008

Keywords

Comments

Jacobsthal numbers ending with the decimal digit 3. - Jianing Song, Aug 30 2022

Crossrefs

The other quadrisections of A001045 are A195156 (first), A139792 (second), and A144864 (third).

Programs

Formula

a(n) = A139792(n) + A013776(n).
a(n+1) - a(n) = 10*A013709(n) = 40*A001025(n).
G.f.: (3-8*x)/((1-x)*(1-16*x)). [Colin Barker, Apr 05 2012]
a(0)=3, a(1)=43, a(n)=17*a(n-1)-16*a(n-2). - Harvey P. Dale, Mar 16 2015
From Jianing Song, Aug 30 2022: (Start)
a(n) = A001045(4*n+3).
a(n) = 10*A141032(n) + 3 = 20*A098704(n+1) + 1 = 40*A131865(n-1) + 1 for n >= 1. (End)

A218728 a(n) = (25^n - 1)/24.

Original entry on oeis.org

0, 1, 26, 651, 16276, 406901, 10172526, 254313151, 6357828776, 158945719401, 3973642985026, 99341074625651, 2483526865641276, 62088171641031901, 1552204291025797526, 38805107275644938151, 970127681891123453776, 24253192047278086344401, 606329801181952158610026
Offset: 0

Views

Author

M. F. Hasler, Nov 04 2012

Keywords

Comments

Partial sums of powers of 25 (A009969); q-integers for q=25.
Partial sums are in A014914. Also, the sequence is related to A014943 by A014943(n) = n*a(n) - Sum_{i=0..n-1} a(i) for n > 0. - Bruno Berselli, Nov 07 2012

Crossrefs

Programs

Formula

a(n) = floor(25^n/24).
From Vincenzo Librandi, Nov 07 2012: (Start)
G.f.: x/((1-x)*(1-25*x)).
a(n) = 26*a(n-1) - 25*a(n-2). (End)
E.g.f.: exp(13*x)*sinh(12*x)/12. - Elmo R. Oliveira, Aug 27 2024
a(n) = 25*a(n-1) + 1. - Jerzy R Borysowicz, Sep 05 2025

A218743 a(n) = (40^n - 1)/39.

Original entry on oeis.org

0, 1, 41, 1641, 65641, 2625641, 105025641, 4201025641, 168041025641, 6721641025641, 268865641025641, 10754625641025641, 430185025641025641, 17207401025641025641, 688296041025641025641, 27531841641025641025641, 1101273665641025641025641, 44050946625641025641025641
Offset: 0

Views

Author

M. F. Hasler, Nov 04 2012

Keywords

Comments

Partial sums of powers of 40 (A009983).

Crossrefs

Programs

  • Magma
    [n le 2 select n-1 else 41*Self(n-1) - 40*Self(n-2): n in [1..20]]; // Vincenzo Librandi, Nov 07 2012
  • Mathematica
    LinearRecurrence[{41, -40}, {0, 1}, 30] (* Vincenzo Librandi, Nov 07 2012 *)
  • Maxima
    A218743(n):=floor(40^n/39)$ makelist(A218743(n),n,0,30); /* Martin Ettl, Nov 05 2012 */
    
  • PARI
    a(n)=40^n\39
    

Formula

a(n) = floor(40^n/39).
From Vincenzo Librandi, Nov 07 2012: (Start)
G.f.: x/((1-x)*(1-40*x)).
a(n) = 41*a(n-1) - 40*a(n-2). (End)
E.g.f.: exp(x)*(exp(39*x) - 1)/39. - Elmo R. Oliveira, Aug 29 2024

A269025 a(n) = Sum_{k = 0..n} 60^k.

Original entry on oeis.org

1, 61, 3661, 219661, 13179661, 790779661, 47446779661, 2846806779661, 170808406779661, 10248504406779661, 614910264406779661, 36894615864406779661, 2213676951864406779661, 132820617111864406779661, 7969237026711864406779661, 478154221602711864406779661
Offset: 0

Views

Author

Ilya Gutkovskiy, Feb 18 2016

Keywords

Comments

Partial sums of powers of 60 (A159991).
Converges in a 10-adic sense to ...762711864406779661.
More generally, the ordinary generating function for the Sum_{k = 0..n} m^k is 1/((1 - m*x)*(1 - x)). Also, Sum_{k = 0..n} m^k = (m^(n + 1) - 1)/(m - 1).

Crossrefs

Cf. A159991.
Cf. similar sequences of the form (k^n-1)/(k-1): A000225 (k=2), A003462 (k=3), A002450 (k=4), A003463 (k=5), A003464 (k=6), A023000 (k=7), A023001 (k=8), A002452 (k=9), A002275 (k=10), A016123 (k=11), A016125 (k=12), A091030 (k=13), A135519 (k=14), A135518 (k=15), A131865 (k=16), A091045 (k=17), A218721 (k=18), A218722 (k=19), A064108 (k=20), A218724-A218734 (k=21..31), A132469 (k=32), A218736-A218753 (k=33..50), this sequence (k=60), A133853 (k=64), A094028 (k=100), A218723 (k=256), A261544 (k=1000).

Programs

  • Mathematica
    Table[Sum[60^k, {k, 0, n}], {n, 0, 15}]
    Table[(60^(n + 1) - 1)/59, {n, 0, 15}]
    LinearRecurrence[{61, -60}, {1, 61}, 15]
  • PARI
    a(n)=60^n + 60^n\59 \\ Charles R Greathouse IV, Jul 26 2016

Formula

G.f.: 1/((1 - 60*x)*(1 - x)).
a(n) = (60^(n + 1) - 1)/59 = 60^n + floor(60^n/59).
a(n+1) = 60*a(n) + 1, a(0)=1.
a(n) = Sum_{k = 0..n} A159991(k).
Sum_{n>=0} 1/a(n) = 1.016671221665660580331...
E.g.f.: exp(x)*(60*exp(59*x) - 1)/59. - Stefano Spezia, Mar 23 2023
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