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 1-3 of 3 results.

A293543 a(n) = ceiling(Fibonacci(n)/3).

Original entry on oeis.org

0, 1, 1, 1, 1, 2, 3, 5, 7, 12, 19, 30, 48, 78, 126, 204, 329, 533, 862, 1394, 2255, 3649, 5904, 9553, 15456, 25009, 40465, 65473, 105937, 171410, 277347, 448757, 726103, 1174860, 1900963, 3075822, 4976784, 8052606, 13029390, 21081996, 34111385, 55193381
Offset: 0

Views

Author

Clark Kimberling, Oct 12 2017

Keywords

Comments

a(n) is the least integer k such that k/Fibonacci(n) > 1/3.

Crossrefs

Cf. A000045.
Cf. A004696 (floor(Fibonacci(n)/3)).
Cf. A293544 (round(Fibonacci(n)/3)).

Programs

  • Mathematica
    LinearRecurrence[{1, 1, 0, 0, 0, 0, 0, 1, -1, -1}, {0, 1, 1, 1, 1, 2, 3, 5, 7, 12}, 50] (* Harvey P. Dale, Oct 18 2018 *)
    Table[Ceiling[Fibonacci[n]/3], {n, 0, 20}] (* Eric W. Weisstein, Feb 07 2025 *)
    Ceiling[Fibonacci[Range[0, 20]]/3] (* Eric W. Weisstein, Feb 07 2025 *)
    CoefficientList[Series[-x (-1 + x^2 + x^3 + x^7 + x^8)/((-1 + x) (1 + x) (1 + x^2) (-1 + x + x^2) (1 + x^4)), {x, 0, 20}], x] (* Eric W. Weisstein, Feb 07 2025 *)
    Table[(9 - 6 Cos[n Pi/2] + 8 Fibonacci[n] - (-1)^n (3 + 4 Sin[n Pi/4] (Cos[n Pi/2] + Sqrt[2] Sin[n Pi/2])))/24, {n, 0, 20}] (* Eric W. Weisstein, Feb 07 2025 *)

Formula

G.f.: -((x (-1 + x^2 + x^3 + x^7 + x^8))/((-1 + x) (1 + x) (1 + x^2) (-1 + x + x^2) (1 + x^4))).
a(n) = a(n-1) + a(n-2) + a(n-8) - a(n-9) - a(n-10) for n >= 11.

A293544 a(n) = round(Fibonacci(n)/3).

Original entry on oeis.org

0, 0, 0, 1, 1, 2, 3, 4, 7, 11, 18, 30, 48, 78, 126, 203, 329, 532, 861, 1394, 2255, 3649, 5904, 9552, 15456, 25008, 40464, 65473, 105937, 171410, 277347, 448756, 726103, 1174859, 1900962, 3075822, 4976784, 8052606, 13029390, 21081995, 34111385, 55193380
Offset: 0

Views

Author

Clark Kimberling, Oct 12 2017

Keywords

Comments

a(n) is the integer k that minimizes | k/Fibonacci(n) - 1/3 |.

Crossrefs

Cf. A000045 (Fibonacci(n)).
Cf. A004696 (floor(Fibonacci(n)/3)).
Cf. A293543 (ceiling(Fibonacci(n)/3)).

Programs

  • Mathematica
    Table[Round[Fibonacci[n]/3], {n, 0, 20}] (* Eric W. Weisstein, Feb 08 2025 *)
    Round[Fibonacci[Range[0, 20]]/3] (* Eric W. Weisstein, Feb 08 2025 *)
    LinearRecurrence[{1, 1, 0, -1, 1, 1}, {0, 0, 1, 1, 2, 3}, {0, 20}] (* Eric W. Weisstein, Feb 08 2025 *)
    CoefficientList[Series[-(x^3/((-1 + x + x^2) (1 + x^4))), {x, 0, 20}], x] (* Eric W. Weisstein, Feb 08 2025 *)
    Table[(Fibonacci[n] + (-1)^n Sin[n Pi/4] (Cos[n Pi/2] + Sqrt[2] Sin[n Pi/2]))/3, {n, 0, 20}] (* Eric W. Weisstein, Feb 08 2025 *)

Formula

G.f.: -(x^2/((-1 + x + x^2) (1 + x^4))).
a(n) = a(n-1) + a(n-2) - a(n-4) + a(n-5) + a(n-6) for n >= 7.

A179001 Partial sums of floor(Fibonacci(n)/3).

Original entry on oeis.org

0, 0, 0, 0, 1, 2, 4, 8, 15, 26, 44, 73, 121, 198, 323, 526, 855, 1387, 2248, 3641, 5896, 9544, 15447, 24999, 40455, 65463, 105927, 171399, 277336, 448745, 726091, 1174847, 1900950, 3075809, 4976771, 8052592, 13029376, 21081981, 34111370, 55193365, 89304750
Offset: 0

Views

Author

Mircea Merca, Jan 03 2011

Keywords

Comments

Partial sums of A004696.

Examples

			a(9) = 0 + 0 + 0 + 0 + 1 + 1 + 2 + 4 + 7 + 11 = 26.
		

Crossrefs

Cf. A004696.

Programs

  • Magma
    [Floor(Fibonacci(n+2)/3-3*n/8-1/6): n in [0..40]]; // Vincenzo Librandi, Apr 28 2011
  • Maple
    A179001 := proc(n) add( floor(combinat[fibonacci](i)/3),i=0..n) ; end proc:
  • Mathematica
    Accumulate[Floor[Fibonacci[Range[0,40]]/3]] (* Harvey P. Dale, Jun 13 2022 *)

Formula

a(n) = round(Fibonacci(n+2)/3 - 3*n/8 - 11/24).
a(n) = round(Fibonacci(n+2)/3 - 3*n/8 - 1/3).
a(n) = floor(Fibonacci(n+2)/3 - 3*n/8 - 1/6).
a(n) = ceiling(Fibonacci(n+2)/3 - 3*n/8 - 3/4).
a(n) = a(n-8) + Fibonacci(n-1) + Fibonacci(n-3) - 3, n > 8.
a(n) = 2*a(n-1) - a(n-3) + a(n-8) - 2*a(n-9) + a(n-11), n > 10.
G.f.: -x^4*(1 + x^4 + x^3) / ( (1+x)*(x^2+1)*(x^2+x-1)*(x^4+1)*(x-1)^2 ).
Showing 1-3 of 3 results.