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 1-2 of 2 results.

A092073 Boustrophedon transform (first version) of Fibonacci numbers 1, 1, 2, 3, 5, 8, ...

Original entry on oeis.org

1, 2, 4, 10, 30, 101, 395, 1769, 9020, 51674, 328936, 2303323, 17595765, 145622477, 1297884212, 12393874652, 126242962310, 1366268975165, 15656289178423, 189374961382141, 2411196896699700, 32235328003898918, 451476237890591144, 6610630095177242675
Offset: 0

Views

Author

N. J. A. Sloane, Apr 01 2004

Keywords

Crossrefs

Cf. A000687, A000738, A000744 (which uses BOUS2), A062122 (which uses Fibonacci numbers with an error in them), A092090.

Programs

  • Maple
    read transforms; with(combinat, fibonacci): a := [seq(fibonacci(i),i=1..50)]: BOUS(a);

Formula

E.g.f.: (sec(x) + tan(x))*((exp(a*x) - exp(b*x))/(a - b) + 1), where a = (1 + sqrt(5))/2 and b = (1 - sqrt(5))/2. - Petros Hadjicostas, Feb 16 2021

Extensions

Entry revised by N. J. A. Sloane, Mar 16 2011

A092090 Boustrophedon transform of Fibonacci numbers 1, 2, 3, 5, 8, ...

Original entry on oeis.org

1, 3, 8, 22, 67, 229, 897, 4023, 20512, 117516, 748031, 5237959, 40014097, 331156423, 2951484420, 28184585550, 287085799927, 3106996356945, 35603555478689, 430652619722011, 5483239453957132, 73305511708044652, 1026690239891085363, 15033060056592047307
Offset: 0

Views

Author

N. J. A. Sloane, Apr 01 2004

Keywords

Crossrefs

Cf. A000744 (which uses BOUS2), A062122 (which uses Fibonacci numbers with an error in them), A092073.

Programs

  • Maple
    read transforms; with(combinat, fibonacci): a := [seq(fibonacci(i),i=2..30)]: BOUS2(a);
  • Python
    from itertools import accumulate, islice
    def A092090_gen(): # generator of terms
        blist, a, b = tuple(), 1, 2
        while True:
            yield (blist := tuple(accumulate(reversed(blist),initial=a)))[-1]
            a, b = b, a+b
    A092090_list = list(islice(A092090_gen(),40)) # Chai Wah Wu, Jun 12 2022

Formula

E.g.f.: (sec(x) + tan(x))*(a^2*exp(a*x) - b^2*exp(b*x))/(a - b), where a = (1 + sqrt(5))/2 and b = (1 - sqrt(5))/2. - Petros Hadjicostas, Feb 16 2021
Showing 1-2 of 2 results.