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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A159674 Expansion of (1 - x)/(1 - 32*x + x^2).

Original entry on oeis.org

1, 31, 991, 31681, 1012801, 32377951, 1035081631, 33090234241, 1057852414081, 33818187016351, 1081124132109151, 34562154040476481, 1104907805163138241, 35322487611179947231, 1129214695752595173151, 36099547776471865593601, 1154056314151347103822081
Offset: 0

Views

Author

Paul Weisenhorn, Apr 19 2009

Keywords

Comments

Previous name was: The general form of the recurrences are the a(j), b(j) and n(j) solutions of the 2 equations problem: 15*n(j) + 1 = a(j)*a(j) and 17*n(j) + 1 = b(j)*b(j) with positive integers.
Positive values of x (or y) satisfying x^2 - 32*x*y + y^2 + 30 = 0. - Colin Barker, Feb 24 2014

Links

Crossrefs

Cf. A029548, A157456, A159675, A159677.
Cf. similar sequences listed in A238379.

Programs

  • Magma
    A029548:= func< n | Evaluate(ChebyshevSecond(n),16) >;
[A029548(n+1) -A029548(n): n in [0..30]]; // G. C. Greubel, Sep 25 2022
  • Maple
    for a from 1 by 2 to 100000 do b:=sqrt((17*a*a-2)/15): if (trunc(b)=b) then
n:=(a*a-1)/15: La:=[op(La),a]:Lb:=[op(Lb),b]:Ln:=[op(Ln),n]: endif: enddo:
# Second program
seq(simplify(ChebyshevU(n, 16) -ChebyshevU(n-1, 16)), n=0..30); # G. C. Greubel, Sep 25 2022
  • Mathematica
    CoefficientList[Series[(1-x)/(1-32*x+x^2), {x, 0, 40}], x] (* Vincenzo Librandi, Feb 26 2014 *)
LinearRecurrence[{32,-1},{1,31},30] (* Harvey P. Dale, Mar 21 2017 *)
  • PARI
    concat([0], Vec((-x+1)/(x^2-32*x+1) + O(x^100))) \\ Colin Barker, Feb 24 2014
  • SageMath
    def A159674(n): return chebyshev_U(n, 16) - chebyshev_U(n-1, 16)
[A159674(n) for n in range(31)] # G. C. Greubel, Sep 25 2022

Formula

The a(j) recurrence is: a(0)=1, a(1)=31, a(t+2) = 32*a(t+1) - a(t) resulting in terms 1, 31, 991, 31681, ... (this sequence).
The b(j) recurrence is: b(0)=1, b(1)=33, b(t+2) = 32*b(t+1) - b(t) resulting in terms 1, 33, 1055, 33727, ... (A159675).
The n(j) recurrence is: n(-1) = n(0) = 0, n(1) = 64, n(t+3) = 1023*(n(t+2) -n(t+1)) + n(t) resulting in terms 0, 0, 64, 65472, 66912384, ... (A159677).
a(n) = (1/34)*(17-sqrt(255))*(1+(16+sqrt(255))^(2*n+1))/(16+sqrt(255))^n. - Bruno Berselli, Feb 25 2014
a(n) = ChebyshevU(n, 16) - ChebyshevU(n-1, 16) = A029548(n) - A029548(n-1). - G. C. Greubel, Sep 25 2022

Extensions

More terms and new name from Colin Barker, Feb 24 2014
Set offset to 0 by Joerg Arndt, Feb 25 2014

A159677 Expansion of 64*x^2/(1 - 1023*x + 1023*x^2 - x^3).

Original entry on oeis.org

0, 0, 64, 65472, 66912384, 68384391040, 69888780730560, 71426265522241344, 72997573474949923072, 74603448665133299138304, 76244651538192756769423680, 77921959268584332285051862720, 79636166127841649402566234276224, 81388083860694897105090406378438272
Offset: 0

Views

Author

Paul Weisenhorn, Apr 19 2009

Keywords

Comments

Previous name was: The general form of the recurrences are the a(j), b(j) and n(j) solutions of the 2 equations problem: 15*n(j) + 1 = a(j)*a(j) and 17*n(j) + 1 = b(j)*b(j) with positive integer numbers.

Links

Crossrefs

Cf. A157456, A159674, A159675.

Programs

  • Magma
    I:=[0,0,64]; [n le 3 select I[n] else 1023*Self(n-1) - 1023*Self(n-2) +Self(n-3): n in [1..30]]; // G. C. Greubel, Jun 03 2018
  • Maple
    for a from 1 by 2 to 100000 do b:=sqrt((17*a*a-2)/15): if (trunc(b)=b) then
n:=(a*a-1)/15: La:=[op(La),a]:Lb:=[op(Lb),b]:Ln:=[op(Ln),n]: endif: enddo:
  • Mathematica
    RecurrenceTable[{a[0]==a[1]==0,a[2]==64,a[n]==1023(a[n-1]-a[n-2])+ a[n-3]}, a,{n,20}] (* Harvey P. Dale, Jan 01 2014 *)
LinearRecurrence[{1023,-1023,1},{0,0,64},20] (* Harvey P. Dale, Jan 01 2014 *)
  • PARI
    concat([0, 0], Vec(64/(-x^3+1023*x^2-1023*x+1) + O(x^20))) \\ Colin Barker, Mar 04 2014
  • PARI
    a(n) = round(-((511+32*sqrt(255))^(-n)*(-1+(511+32*sqrt(255))^n)*(16+sqrt(255)+(-16+sqrt(255))*(511+32*sqrt(255))^n))/510) \\ Colin Barker, Jul 25 2016
  • SageMath
    def A159677(n): return (16/255)*(-1 +chebyshev_U(n, 511) -1021*chebyshev_U(n-1, 511))
[A159677(n) for n in range(31)] # G. C. Greubel, Sep 25 2022

Formula

The a(j) recurrence is a(0)=1, a(1)=31, a(t+2) = 32*a(t+1) - a(t) resulting in terms 1, 31, 991, 31681, ... (A159674).
The b(j) recurrence is b(0)=1, b(1)=33, b(t+2) = 32*b(t+1) - b(t) resulting in terms 1, 33, 1055, 33727, ... (A159675).
The n(j) recurrence is n(-1) = n(0) = 0, n(1) = 64, n(t+3) = 1023*(n(t+2) -n(t+1)) + n(t) resulting in terms 0, 0, 64, 65472, 66912384, ... (this sequence).
a(n) = -((511+32*sqrt(255))^(-n)*(-1+(511+32*sqrt(255))^n)*(16+sqrt(255)+(-16+sqrt(255))*(511+32*sqrt(255))^n))/510. - Colin Barker, Jul 25 2016
a(n) = (16/255)*(-1 + ChebyshevU(n, 511) - 1021*ChebyshevU(n-1, 511)). - G. C. Greubel, Sep 25 2022

Extensions

More terms from Harvey P. Dale, Jan 01 2014
New name from Colin Barker, Feb 24 2014
Offset changed to 0 by Colin Barker, Mar 04 2014
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