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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A010892 Inverse of 6th cyclotomic polynomial. A period 6 sequence.

Original entry on oeis.org

1, 1, 0, -1, -1, 0, 1, 1, 0, -1, -1, 0, 1, 1, 0, -1, -1, 0, 1, 1, 0, -1, -1, 0, 1, 1, 0, -1, -1, 0, 1, 1, 0, -1, -1, 0, 1, 1, 0, -1, -1, 0, 1, 1, 0, -1, -1, 0, 1, 1, 0, -1, -1, 0, 1, 1, 0, -1, -1, 0, 1, 1, 0, -1, -1, 0, 1, 1, 0, -1, -1, 0, 1, 1, 0, -1, -1, 0, 1, 1, 0, -1, -1, 0, 1, 1, 0, -1, -1, 0, 1, 1, 0, -1, -1, 0, 1, 1, 0, -1, -1, 0
Offset: 0

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Author

Keywords

Comments

Any sequence b(n) satisfying the recurrence b(n) = b(n-1) - b(n-2) can be written as b(n) = b(0)*a(n) + (b(1)-b(0))*a(n-1).
a(n) is the determinant of the n X n matrix M with m(i,j)=1 if |i-j| <= 1 and 0 otherwise. - Mario Catalani (mario.catalani(AT)unito.it), Jan 25 2003
Also row sums of triangle in A108299; a(n)=L(n-1,1), where L is also defined as in A108299; see A061347 for L(n,-1). - Reinhard Zumkeller, Jun 01 2005
Pisano period lengths: 1, 3, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, ... - R. J. Mathar, Aug 10 2012
Periodic sequences of this type can also be calculated as a(n) = c + floor(q/(p^m-1)*p^n) mod p, where c is a constant, q is the number representing the periodic digit pattern and m is the period. c, p and q can be calculated as follows: Let D be the array representing the number pattern to be repeated, m = size of D, max = maximum value of elements in D, min = minimum value of elements in D. Then c := min, p := max - min + 1 and q := p^m*Sum_{i=1..m} (D(i)-min)/p^i. Example: D = (1, 1, 0, -1, -1, 0), c = -1, m = 6, p = 3 and q = 676 for this sequence. - Hieronymus Fischer, Jan 04 2013
B(n) = a(n+5) = S(n-1, 1) appears, together with a(n) = A057079(n+1), in the formula 2*exp(Pi*n*i/3) = A(n) + B(n)*sqrt(3)*i with i = sqrt(-1). For S(n, x) see A049310. See also a Feb 27 2014 comment on A099837. - Wolfdieter Lang, Feb 27 2014
a(n) (for n>=1) is the difference between numbers of even and odd permutations p of 1,2,...,n such that |p(i)-i|<=1 for i=1,2,...,n. - Dmitry Efimov, Jan 08 2016
From Tom Copeland, Jan 31 2016: (Start)
Specialization of the o.g.f. 1 / ((x - w1)(x-w2)) = (1/(w1-w2)) ((w1-w2) + (w1^2 - w2^2) x + (w1^3-w2^3) x^2 + ...) with w1*w2 = (1/w1) + (1/w2) = 1. Then w1 = q = e^(i*Pi/3) and w2 = 1/q = e^(-i*Pi/3), giving the o.g.f. 1 /(1-x+x^2) for this entry with a(n) = (2/sqrt(3)) sin((n+1)Pi/3). See the Copeland link for more relations.
a(n) = (q^(n+1) - q^(-(n+1))) / (q - q^(-1)), so this entry gives the o.g.f. for an instance of the quantum integers denoted by [m]_q in Morrison et al. and Tingley. (End)

Examples

			G.f. = 1 + x - x^3 - x^4 + x^6 + x^7 - x^9 - x^10 + x^12 + x^13 - x^15 + ...
		

Crossrefs

a(n) = row sums of signed triangle A049310.
Differs only by a shift from A128834.
a(n+1) = row sums of triangle A130777: repeat(1,0,-1,-1,0,1).

Programs

  • Magma
    &cat[[1,1,0,-1,-1,0]: n in [0..20]]; // Vincenzo Librandi, Apr 03 2014
  • Maple
    a:=n->coeftayl(1/(x^2-x+1), x=0, n);
    a:=n->2*sin(Pi*(n+1)/3)/sqrt(3);
    A010892:=n->[1,1,0,-1,-1,0][irem(n,6)+1];
    A010892:=n->Array(0..5,[1,1,0,-1,-1,0])[irem(n,6)];
    A010892:=n->table([0=1,1=1,2=0,3=-1,4=-1,5=0])[irem(n,6)];
    with(numtheory,cyclotomic); c := series(1/cyclotomic(6,x),x,102): seq(coeff(c,x,n),n=0..101); # Rainer Rosenthal, Jan 01 2007
  • Mathematica
    a[n_] := {1, 1, 0, -1, -1, 0}[[Mod[n, 6] + 1]]; Table[a[n], {n, 0, 101}] (* Jean-François Alcover, Jul 19 2013 *)
    CoefficientList[Series[1/Cyclotomic[6, x], {x, 0, 100}], x] (* Vincenzo Librandi, Apr 03 2014 *)
    PadRight[{},120,{1,1,0,-1,-1,0}] (* Harvey P. Dale, Jul 07 2020 *)
  • PARI
    {a(n) = (-1)^(n\3) * sign((n + 1)%3)}; /* Michael Somos, Sep 23 2005 */
    
  • PARI
    {a(n) = subst( poltchebi(n) + poltchebi(n-1), 'x, 1/2) * 2/3}; /* Michael Somos, Sep 23 2005 */
    
  • PARI
    {a(n) = [1, 1, 0, -1, -1, 0][n%6 + 1]}; /* Michael Somos, Feb 14 2006 */
    
  • PARI
    {a(n) = my(A, p, e); if( n<0, 0, n++; A = factor(n); prod( k=1, matsize(A)[1], [p, e] = A[k, ]; if( p==2, -(-1)^e, p==3, 0, p%6 == 1, 1, (-1)^e)))}; /* Michael Somos, Oct 29 2006 */
    
  • Python
    def A010892(n): return [1,1,0,-1,-1,0][n%6] # Alec Mihailovs, Jan 01 2007
    
  • Sage
    [lucas_number1(n,1,+1) for n in range(-5, 97)] # Zerinvary Lajos, Apr 22 2009
    
  • Sage
    def A010892():
        x, y = -1, -1
        while True:
            yield -x
            x, y = y, -x + y
    a = A010892()
    [next(a) for i in range(40)]  # Peter Luschny, Jul 11 2013
    

Formula

G.f.: 1 / (1 - x + x^2).
a(n) = a(n-1) - a(n-2), a(0)=1, a(1)=1.
a(n) = ((-1)^floor(n/3) + (-1)^floor((n+1)/3))/2.
a(n) = 0 if n mod 6 = 2 or 5, a(n) = +1 if n mod 6 = 0 or 1, a(n) = -1 otherwise. a(n) = S(n, 1) = U(n, 1/2) (Chebyshev U(n, x) polynomials).
a(n) = sqrt(4/3)*Im((1/2 + i*sqrt(3/4))^(n+1)). - Henry Bottomley, Apr 12 2000
Binomial transform of A057078. a(n) = Sum_{k=0..n} C(k, n-k)*(-1)^(n-k). - Paul Barry, Sep 13 2003
a(n) = 2*sin(Pi*n/3 + Pi/3)/sqrt(3). - Paul Barry, Jan 28 2004
a(n) = Sum_{k=0..floor(n/2)} C(n-k, k)*(-1)^k. - Paul Barry, Jul 28 2004
Euler transform of length 6 sequence [1, -1, -1, 0, 0, 1]. - Michael Somos, Sep 23 2005
a(n) = a(1 - n) = -a(-2 - n) for all n in Z. - Michael Somos, Feb 14 2006
a(n) = Sum_{k=0..n} (-2)^(n-k) * A085838(n,k). - Philippe Deléham, Oct 26 2006
a(n) = b(n+1) where b(n) is multiplicative with b(2^e) = -(-1)^e if e>0, b(3^e) = 0^e, b(p^e) = 1 if p == 1 (mod 6), b(p^e) = (-1)^e if p == 5 (mod 6). - Michael Somos, Oct 29 2006
Given g.f. A(x), then, B(x) = x * A(x) satisfies 0 = f(B(x), B(x^2)) where f(u, v) = u^2 - v - 2*u*v * (1 - u). - Michael Somos, Oct 29 2006
a(2*n) = A057078(n), a(2*n+1) = A049347(n).
a(n) = Sum_{k=0..n} A109466(n,k). - Philippe Deléham, Nov 14 2006
a(n) = Sum_{k=0..n} A133607(n,k). - Philippe Deléham, Dec 30 2007
a(n) = A128834(n+1). - Jaume Oliver Lafont, Dec 05 2008
a(n) = Sum_{k=0..n} C(n+k+1,2k+1) * (-1)^k. - Paul Barry, Jun 03 2009
a(n) = A101950(n,0) = (-1)^n * A049347(n). - Philippe Deléham, Feb 10 2012
a(n) = Product_{k=1..floor(n/2)} 1 - 4*(cos(k*Pi/(n+1)))^2. - Mircea Merca, Apr 01 2012
G.f.: 1 / (1 - x / (1 + x / (1 - x))). - Michael Somos, Apr 02 2012
a(n) = -1 + floor(181/819*10^(n+1)) mod 10. - Hieronymus Fischer, Jan 03 2013
a(n) = -1 + floor(13/14*3^(n+1)) mod 3. - Hieronymus Fischer, Jan 04 2013
a(n) = 1/(1+r2)*(1/r1)^n + 1/(1+r1)*(1/r2)^n, with r1=(1-i*sqrt(3))/2 and r2=(1+i*sqrt(3))/2. - Ralf Stephan, Jul 19 2013
a(n) = ((n+1)^2 mod 3) * (-1)^floor((n+1)/3). - Wesley Ivan Hurt, Mar 15 2015
a(n-1) = n - Sum_{i=1..n-1} i*a(n-i). - Derek Orr, Apr 28 2015
a(n) = S(2*n+1, sqrt(3))/sqrt(3) = S(n, 1) with S(n, x) coefficients given in A049310. The S(n, 1) formula appeared already above. S(2*n, sqrt(3)) = A057079(n). See also a Feb 27 2014 comment above. - Wolfdieter Lang, Jan 16 2018
E.g.f.: sqrt(exp(x)*4/3) * cos(x*sqrt(3/4) - Pi/6). - Michael Somos, Jul 05 2018
a(n) = Determinant(Tri(n)), for n >= 1, with Tri(n) the n X n tridiagonal matrix with entries 1 (a special Toeplitz matrix). - Wolfdieter Lang, Sep 20 2019
a(n) = Product_{k=1..n}(1 + 2*cos(k*Pi/(n+1))). - Peter Luschny, Nov 28 2019

Extensions

Entry revised by N. J. A. Sloane, Jul 16 2004

A374439 Triangle read by rows: the coefficients of the Lucas-Fibonacci polynomials. T(n, k) = T(n - 1, k) + T(n - 2, k - 2) with initial values T(n, k) = k + 1 for k < 2.

Original entry on oeis.org

1, 1, 2, 1, 2, 1, 1, 2, 2, 2, 1, 2, 3, 4, 1, 1, 2, 4, 6, 3, 2, 1, 2, 5, 8, 6, 6, 1, 1, 2, 6, 10, 10, 12, 4, 2, 1, 2, 7, 12, 15, 20, 10, 8, 1, 1, 2, 8, 14, 21, 30, 20, 20, 5, 2, 1, 2, 9, 16, 28, 42, 35, 40, 15, 10, 1, 1, 2, 10, 18, 36, 56, 56, 70, 35, 30, 6, 2
Offset: 0

Views

Author

Peter Luschny, Jul 22 2024

Keywords

Comments

There are several versions of Lucas and Fibonacci polynomials in this database. Our naming follows the convention of calling polynomials after the values of the polynomials at x = 1. This assumes a regular sequence of polynomials, that is, a sequence of polynomials where degree(p(n)) = n. This view makes the coefficients of the polynomials (the terms of a row) a refinement of the values at the unity.
A remarkable property of the polynomials under consideration is that they are dual in this respect. This means they give the Lucas numbers at x = 1 and the Fibonacci numbers at x = -1 (except for the sign). See the example section.
The Pell numbers and the dual Pell numbers are also values of the polynomials, at the points x = -1/2 and x = 1/2 (up to the normalization factor 2^n). This suggests a harmonized terminology: To call 2^n*P(n, -1/2) = 1, 0, 1, 2, 5, ... the Pell numbers (A000129) and 2^n*P(n, 1/2) = 1, 4, 9, 22, ... the dual Pell numbers (A048654).
Based on our naming convention one could call A162515 (without the prepended 0) the Fibonacci polynomials. In the definition above only the initial values would change to: T(n, k) = k + 1 for k < 1. To extend this line of thought we introduce A374438 as the third triangle of this family.
The triangle is closely related to the qStirling2 numbers at q = -1. For the definition of these numbers see A333143. This relates the triangle to A065941 and A103631.

Examples

			Triangle starts:
  [ 0] [1]
  [ 1] [1, 2]
  [ 2] [1, 2, 1]
  [ 3] [1, 2, 2,  2]
  [ 4] [1, 2, 3,  4,  1]
  [ 5] [1, 2, 4,  6,  3,  2]
  [ 6] [1, 2, 5,  8,  6,  6,  1]
  [ 7] [1, 2, 6, 10, 10, 12,  4,  2]
  [ 8] [1, 2, 7, 12, 15, 20, 10,  8,  1]
  [ 9] [1, 2, 8, 14, 21, 30, 20, 20,  5,  2]
  [10] [1, 2, 9, 16, 28, 42, 35, 40, 15, 10, 1]
.
Table of interpolated sequences:
  |  n | A039834 & A000045 | A000032 |   A000129   |   A048654  |
  |  n |     -P(n,-1)      | P(n,1)  |2^n*P(n,-1/2)|2^n*P(n,1/2)|
  |    |     Fibonacci     |  Lucas  |     Pell    |    Pell*   |
  |  0 |        -1         |     1   |       1     |       1    |
  |  1 |         1         |     3   |       0     |       4    |
  |  2 |         0         |     4   |       1     |       9    |
  |  3 |         1         |     7   |       2     |      22    |
  |  4 |         1         |    11   |       5     |      53    |
  |  5 |         2         |    18   |      12     |     128    |
  |  6 |         3         |    29   |      29     |     309    |
  |  7 |         5         |    47   |      70     |     746    |
  |  8 |         8         |    76   |     169     |    1801    |
  |  9 |        13         |   123   |     408     |    4348    |
		

Crossrefs

Triangles related to Lucas polynomials: A034807, A114525, A122075, A061896, A352362.
Triangles related to Fibonacci polynomials: A162515, A053119, A168561, A049310, A374441.
Sums include: A000204 (Lucas numbers, row), A000045 & A212804 (even sums, Fibonacci numbers), A006355 (odd sums), A039834 (alternating sign row).
Type m^n*P(n, 1/m): A000129 & A048654 (Pell, m=2), A108300 & A003688 (m=3), A001077 & A048875 (m=4).
Adding and subtracting the values in a row of the table (plus halving the values obtained in this way): A022087, A055389, A118658, A052542, A163271, A371596, A324969, A212804, A077985, A069306, A215928.
Columns include: A040000 (k=1), A000027 (k=2), A005843 (k=3), A000217 (k=4), A002378 (k=5).
Diagonals include: A000034 (k=n), A029578 (k=n-1), abs(A131259) (k=n-2).
Cf. A029578 (subdiagonal), A124038 (row reversed triangle, signed).

Programs

  • Magma
    function T(n,k) // T = A374439
      if k lt 0 or k gt n then return 0;
      elif k le 1 then return k+1;
      else return T(n-1,k) + T(n-2,k-2);
      end if;
    end function;
    [T(n,k): k in [0..n], n in [0..12]]; // G. C. Greubel, Jan 23 2025
    
  • Maple
    A374439 := (n, k) -> ifelse(k::odd, 2, 1)*binomial(n - irem(k, 2) - iquo(k, 2), iquo(k, 2)):
    # Alternative, using the function qStirling2 from A333143:
    T := (n, k) -> 2^irem(k, 2)*qStirling2(n, k, -1):
    seq(seq(T(n, k), k = 0..n), n = 0..10);
  • Mathematica
    A374439[n_, k_] := (# + 1)*Binomial[n - (k + #)/2, (k - #)/2] & [Mod[k, 2]];
    Table[A374439[n, k], {n, 0, 10}, {k, 0, n}]//Flatten (* Paolo Xausa, Jul 24 2024 *)
  • Python
    from functools import cache
    @cache
    def T(n: int, k: int) -> int:
        if k > n: return 0
        if k < 2: return k + 1
        return T(n - 1, k) + T(n - 2, k - 2)
    
  • Python
    from math import comb as binomial
    def T(n: int, k: int) -> int:
        o = k & 1
        return binomial(n - o - (k - o) // 2, (k - o) // 2) << o
    
  • Python
    def P(n, x):
        if n < 0: return P(n, x)
        return sum(T(n, k)*x**k for k in range(n + 1))
    def sgn(x: int) -> int: return (x > 0) - (x < 0)
    # Table of interpolated sequences
    print("|  n | A039834 & A000045 | A000032 |   A000129   |   A048654  |")
    print("|  n |     -P(n,-1)      | P(n,1)  |2^n*P(n,-1/2)|2^n*P(n,1/2)|")
    print("|    |     Fibonacci     |  Lucas  |     Pell    |    Pell*   |")
    f = "| {0:2d} | {1:9d}         |  {2:4d}   |   {3:5d}     |    {4:4d}    |"
    for n in range(10): print(f.format(n, -P(n, -1), P(n, 1), int(2**n*P(n, -1/2)), int(2**n*P(n, 1/2))))
    
  • SageMath
    from sage.combinat.q_analogues import q_stirling_number2
    def A374439(n,k): return (-1)^((k+1)//2)*2^(k%2)*q_stirling_number2(n+1, k+1, -1)
    print(flatten([[A374439(n, k) for k in range(n+1)] for n in range(13)])) # G. C. Greubel, Jan 23 2025

Formula

T(n, k) = 2^k' * binomial(n - k' - (k - k') / 2, (k - k') / 2) where k' = 1 if k is odd and otherwise 0.
T(n, k) = (1 + (k mod 2))*qStirling2(n, k, -1), see A333143.
2^n*P(n, -1/2) = A000129(n - 1), Pell numbers, P(-1) = 1.
2^n*P(n, 1/2) = A048654(n), dual Pell numbers.
T(2*n, n) = (1/2)*(-1)^n*( (1+(-1)^n)*A005809(n/2) - 2*(1-(-1)^n)*A045721((n-1)/2) ). - G. C. Greubel, Jan 23 2025

A133665 a(n) = a(n-1) - 9*a(n-2), a(0) = 1, a(1) = 3.

Original entry on oeis.org

1, 3, -6, -33, 21, 318, 129, -2733, -3894, 20703, 55749, -130578, -632319, 542883, 6233754, 1347807, -54755979, -66886242, 425917569, 1027893747, -2805364374, -12056408097, 13191871269, 121699544142, 2972702721, -1092323194557, -1119077519046, 8711831231967
Offset: 0

Views

Author

Philippe Deléham, Dec 28 2007

Keywords

Crossrefs

Cf. A133607.

Programs

  • Mathematica
    LinearRecurrence[{1,-9},{1,3},40] (* Harvey P. Dale, Apr 21 2019 *)
  • PARI
    Vec((1+2*x)/(1-x+9*x^2) + O(x^30)) \\ Jinyuan Wang, Apr 09 2020

Formula

G.f.: (1+2*x)/(1-x+9*x^2).
a(n) = Sum_{k=0..n} A133607(n,k)*3^k. - Philippe Deléham, Dec 29 2007

Extensions

Corrected and extended by Harvey P. Dale, Apr 21 2019

A133668 a(n) = a(n-1) - 36*a(n-2), a(0)=1, a(1)=6.

Original entry on oeis.org

1, 6, -30, -246, 834, 9690, -20334, -369174, 362850, 13653114, 590514, -490921590, -512180094, 17160997146, 35599480530, -582196416726, -1863777715806, 19095293286330, 86191291055346, -601239267252534, -3704125745244990, 17940487875846234
Offset: 0

Views

Author

Philippe Deléham, Dec 28 2007

Keywords

Programs

  • Mathematica
    CoefficientList[Series[(1+5x)/(1-x+36x^2),{x,0,40}],x] (* or *) LinearRecurrence[{1,-36},{1,6},40] (* Harvey P. Dale, Dec 28 2022 *)
  • PARI
    a(n)=([0,1; -36,1]^n*[1;6])[1,1] \\ Charles R Greathouse IV, Feb 15 2017

Formula

G.f.:(1+5*x)/(1-x+36*x^2).
a(n) = Sum_{k=0..n} A133607(n,k)*6^k. - Philippe Deléham, Dec 30 2007

Extensions

a(18) corrected by Matthew House, Feb 15 2017

A133631 a(n) = a(n-1) - 4*a(n-2), a(0)=1, a(1)=2.

Original entry on oeis.org

1, 2, -2, -10, -2, 38, 46, -106, -290, 134, 1294, 758, -4418, -7450, 10222, 40022, -866, -160954, -157490, 486326, 1116286, -829018, -5294162, -1978090, 19198558, 27110918, -49683314, -158126986, 40606270, 673114214, 510689134, -2181767722, -4224524258
Offset: 0

Views

Author

Philippe Deléham, Dec 28 2007

Keywords

Examples

			G.f. = 1 + 2*x - 2*x^2 - 10*x^3 - 2*x^4 + 38*x^5 + 46*x^6 - 106*x^7 + ... - _Michael Somos_, Oct 24 2023
		

Crossrefs

Programs

  • Mathematica
    a[ n_] := 2^n * ChebyshevU[n, 1/4] + 2^(n-1) * ChebyshevU[n-1, 1/4]; (* Michael Somos, Oct 24 2023 *)
    LinearRecurrence[{1,-4},{1,2},50] (* Harvey P. Dale, Feb 01 2025 *)
  • PARI
    {a(n) = 2^n*polchebyshev(n, 2, 1/4) + 2^(n-1)*polchebyshev(n-1, 2, 1/4)}; /* Michael Somos, Oct 24 2023 */

Formula

G.f.: (1+x)/(1-x+4*x^2).
a(n) = Sum_{k=0..n} A133607(n,k)*2^k. - Philippe Deléham, Dec 29 2007
a(n) = 2^n*U(n, 1/4) + 2^(n-1)*U(n-1, 1/4) = A106853(n) + A106853(n-1) where U is the Chebyshev polynomial of the 2nd kind. - Michael Somos, Oct 24 2023

A133666 a(n) = a(n-1) - 16*a(n-2), a(0)=1, a(1)=4.

Original entry on oeis.org

1, 4, -12, -76, 116, 1332, -524, -21836, -13452, 335924, 551156, -4823628, -13642124, 63535924, 281809908, -734764876, -5243723404, 6512514612, 90412089076, -13788144716, -1460381569932, -1239771254476, 22126333864436, 41962673936052
Offset: 0

Views

Author

Philippe Deléham, Dec 28 2007, corrected Jan 04 2008

Keywords

Formula

G.f.: (1+3*x) / (1-x+16*x^2).
a(n) = Sum_{k=0..n} A133607(n,k)*4^k. - Philippe Deléham, Dec 29 2007

Extensions

a(19) corrected and more terms from Sean A. Irvine, May 19 2019

A133667 a(n) = a(n-1) - 25*a(n-2), a(0)=1, a(1)=5.

Original entry on oeis.org

1, 5, -20, -145, 355, 3980, -4895, -104395, 17980, 2627855, 2178355, -63518020, -117976895, 1469973605, 4419395980, -32329944145, -142814843645, 665433759980, 4235804851105, -12400039148395, -118295160426020, 191705818283855
Offset: 0

Views

Author

Philippe Deléham, Dec 28 2007

Keywords

Crossrefs

Cf. A133607.

Programs

  • Mathematica
    LinearRecurrence[{1,-25},{1, 5}, 22] (* Georg Fischer, May 02 2019 *)
  • PARI
    Vec((1+4*x)/(1-x+25*x^2) + O(x^30)) \\ Michel Marcus, May 02 2019

Formula

G.f.: (1+4*x)/(1-x+25*x^2).
a(n) = Sum_{k=0..n} A133607(n,k)*5^k. - Philippe Deléham, Dec 29 2007

Extensions

a(10) corrected by Georg Fischer, May 02 2019

A133669 a(n) = a(n-1) - 49*a(n-2), a(0)=1, a(1)=7.

Original entry on oeis.org

1, 7, -42, -385, 1673, 20538, -61439, -1067801, 1942710, 54264959, -40927831, -2699910822, -694447103, 131601183175, 165629091222, -6282828884353, -14398654354231, 293459960979066, 998994024336385, -13380544063637849, -62331251256120714
Offset: 0

Views

Author

Philippe Deléham, Dec 28 2007

Keywords

Crossrefs

Cf. A133607.

Programs

  • Mathematica
    LinearRecurrence[{1,-49},{1,7},20] (* or *)  CoefficientList[ Series[ (1+6x)/(1-x+49x^2),{x,0,20}],x] (* Harvey P. Dale, Sep 08 2018 *)

Formula

G.f.: (1+6*x)/(1-x+49*x^2) .
a(n) = Sum_{k=0..n} A133607(n,k)*7^k. - Philippe Deléham, Dec 30 2007

Extensions

More terms from Harvey P. Dale, Sep 08 2018

A133671 a(n) = a(n-1) - 64*a(n-2), a(0)=1, a(1)=8.

Original entry on oeis.org

1, 8, -56, -568, 3016, 39368, -153656, -2673208, 7160776, 178246088, -280043576, -11687793208, 6234995656, 754253760968, 355214038984, -47917026662968, -70650725157944, 2996038981272008, 7517685391380424, -184228809410028088
Offset: 0

Views

Author

Philippe Deléham, Dec 29 2007

Keywords

Crossrefs

Cf. A133607.

Formula

G.f.: (1+7*x)/(1-x+64*x^2).
a(n) = Sum_{k=0..n} A133607(n,k)*8^k. - Philippe Deléham, Dec 30 2007

A133672 a(n) = a(n-1) - 81*a(n-2), a(0)=1, a(1)=9.

Original entry on oeis.org

1, 9, -72, -801, 5031, 69912, -337599, -6000471, 21345048, 507383199, -1221565689, -42319604808, 56627216001, 3484515205449, -1102289290632, -283348020932001, -194062588390809, 22757127107101272, 38476196766756801, -1804851098908446231
Offset: 0

Views

Author

Philippe Deléham, Dec 29 2007

Keywords

Programs

  • Mathematica
    LinearRecurrence[{1,-81},{1,9},30] (* Harvey P. Dale, Aug 01 2016 *)

Formula

G.f.: (1+8*x)/(1-x+81*x^2).
a(n) = Sum_{k=0..n} A133607(n,k)*9^k. - Philippe Deléham, Dec 30 2007
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