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 1-4 of 4 results.

A097135 a(0) = 1; for n>0, a(n) = 3*Fibonacci(n).

Original entry on oeis.org

1, 3, 3, 6, 9, 15, 24, 39, 63, 102, 165, 267, 432, 699, 1131, 1830, 2961, 4791, 7752, 12543, 20295, 32838, 53133, 85971, 139104, 225075, 364179, 589254, 953433, 1542687, 2496120, 4038807, 6534927, 10573734, 17108661, 27682395, 44791056, 72473451, 117264507
Offset: 0

Views

Author

Paul Barry, Jul 26 2004

Keywords

Comments

Binomial transform is A097136.

Crossrefs

Essentially the same as A022086.

Programs

Formula

G.f. : (1+2*x-x^2)/(1-x-x^2).
a(n) = a(n-1)+a(n-2) for n>2.
a(2n) = A097134(n); a(2n+1) = 3*F(2n+1).

Extensions

Definition rewritten by N. J. A. Sloane, Jan 24 2010

A097133 a(n) = 3*Fibonacci(n) + (-1)^n.

Original entry on oeis.org

1, 2, 4, 5, 10, 14, 25, 38, 64, 101, 166, 266, 433, 698, 1132, 1829, 2962, 4790, 7753, 12542, 20296, 32837, 53134, 85970, 139105, 225074, 364180, 589253, 953434, 1542686, 2496121, 4038806, 6534928, 10573733, 17108662, 27682394, 44791057, 72473450, 117264508
Offset: 0

Views

Author

Paul Barry, Jul 26 2004

Keywords

Comments

Binomial transform is A097134.

Crossrefs

Programs

  • Haskell
    a097133 n = a097133_list !! n
    a097133_list = 1 : 2 : 4 : zipWith (+)
                   (map (* 2) $ tail a097133_list) a097133_list
    -- Reinhard Zumkeller, Feb 24 2015
  • Mathematica
    CoefficientList[Series[(1+2x+2x^2)/((1+x)(1-x-x^2)),{x,0,40}],x] (* or *) LinearRecurrence[{0,2,1},{1,2,4},40] (* Harvey P. Dale, May 07 2011 *)

Formula

G.f.: (1+2*x+2*x^2)/((1+x)*(1-x-x^2));
a(n) = 2*a(n-2)+a(n-3);
a(2*n) = 3*F(2*n)+1 = A097136(n).

A192908 Constant term in the reduction by (x^2 -> x + 1) of the polynomial p(n,x) defined below at Comments.

Original entry on oeis.org

1, 1, 3, 7, 17, 43, 111, 289, 755, 1975, 5169, 13531, 35423, 92737, 242787, 635623, 1664081, 4356619, 11405775, 29860705, 78176339, 204668311, 535828593, 1402817467, 3672623807, 9615053953, 25172538051, 65902560199
Offset: 0

Views

Author

Clark Kimberling, Jul 12 2011

Keywords

Comments

The titular polynomial is defined by p(n,x) = (x^2)*p(n-1,x) + x*p(n-2,x), with p(0,x) = 1, p(1,x) = x + 1.

Crossrefs

Cf. A000045; A052995: 2*Fibonacci(2*n-1) for n>0.

Programs

  • GAP
    Concatenation([1], List([1..30], n -> 1+2*Fibonacci(2*(n-1)))); # G. C. Greubel, Jan 11 2019
  • Magma
    [1] cat [1+2*Fibonacci(2*(n-1)): n in [1..30]]; // G. C. Greubel, Jan 11 2019
    
  • Mathematica
    u = 1; v = 1; a = 1; b = 1; c = 1; d = 1; e = 0; f = 1;
    q = x^2; s = u*x + v; z = 26;
    p[0, x_] := a;  p[1, x_] := b*x + c
    p[n_, x_] := d*(x^2)*p[n - 1, x] + e*x*p[n - 2, x] + f;
    Table[Expand[p[n, x]], {n, 0, 8}]
    reduce[{p1_, q_, s_, x_}]:= FixedPoint[(s PolynomialQuotient @@ #1 + PolynomialRemainder @@ #1 &)[{#1, q, x}] &, p1]
    t = Table[reduce[{p[n, x], q, s, x}], {n, 0, z}];
    u0 = Table[Coefficient[Part[t, n], x, 0], {n, 1, z}]    (* A192908 *)
    u1 = Table[Coefficient[Part[t, n], x, 1], {n, 1, z}]    (* A069403 *)
    Simplify[FindLinearRecurrence[u0]] (* recurrence for 0-sequence *)
    Simplify[FindLinearRecurrence[u1]] (* recurrence for 1-sequence *)
    LinearRecurrence[{4,-4,1}, {1,1,3,7}, 30] (* G. C. Greubel, Jan 11 2019 *)
  • PARI
    vector(30, n, n--; if(n==0,1,1+2*fibonacci(2*n-2))) \\ G. C. Greubel, Jan 11 2019
    
  • Sage
    [1]+[1+2*fibonacci(2*(n-1)) for n in (1..30)] # G. C. Greubel, Jan 11 2019
    

Formula

a(n) = 4*a(n-1) - 4*a(n-2) + a(n-3) for n>3.
G.f.: 1 + x*(1 - x - x^2)/((1 - x)*(1 - 3*x + x^2)). - R. J. Mathar, Jul 13 2011
a(n) = 2*Fibonacci(2*n-2) + 1 for n>0, a(0)=1. - Bruno Berselli, Dec 27 2016
a(n) = -1 + 3*a(n-1) - a(n-2) with a(1) = 1 and a(2) = 3. Cf. A055588 and A097136. - Peter Bala, Nov 12 2017

A097132 a(n) = Sum_{k=0..n} Fibonacci(k) + (-1)^k*Fibonacci(k-1).

Original entry on oeis.org

1, 2, 4, 5, 10, 12, 25, 30, 64, 77, 166, 200, 433, 522, 1132, 1365, 2962, 3572, 7753, 9350, 20296, 24477, 53134, 64080, 139105, 167762, 364180, 439205, 953434, 1149852, 2496121, 3010350, 6534928, 7881197, 17108662, 20633240, 44791057
Offset: 0

Views

Author

Paul Barry, Jul 26 2004

Keywords

Comments

Partial sums of A097131.

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{1,3,-3,-1,1},{1,2,4,5,10},40] (* Harvey P. Dale, Nov 12 2022 *)

Formula

G.f.: (1 + x - x^2 - 2*x^3)/((1 - 3*x^2 + x^4)*(1-x));
a(n) = a(n-1) + 3*a(n-2) - 3*a(n-3) - a(n-4) + a(n-5);
a(n) = 1 + (1/2 - sqrt(5)/2)^n*(1/2 - 3*sqrt(5)/10) - (sqrt(5)/2 - 1/2)^n*(3*sqrt(5)/10 + 1/2) + (-sqrt(5)/2 - 1/2)^n*(3*sqrt(5)/10 - 1/2) + (sqrt(5)/2 + 1/2)^n*(3*sqrt(5)/10 + 1/2);
a(2n) = 1 + 3*Fibonacci(2n) = A097136(n);
a(2n+1) = 1 + Fibonacci(2n) + Fibonacci(2n+2) = 1 + Lucas(2n).
Showing 1-4 of 4 results.