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.

A000738 Boustrophedon transform (first version) of Fibonacci numbers 0,1,1,2,3,...

Original entry on oeis.org

0, 1, 3, 8, 25, 85, 334, 1497, 7635, 43738, 278415, 1949531, 14893000, 123254221, 1098523231, 10490117340, 106851450165, 1156403632189, 13251409502982, 160286076269309, 2040825708462175, 27283829950774822, 382127363497453243, 5595206208670390323
Offset: 0

Views

Author

Keywords

Crossrefs

Programs

  • Haskell
    a000738 n = sum $ zipWith (*) (a109449_row n) a000045_list
    -- Reinhard Zumkeller, Nov 03 2013
    
  • Maple
    read(transforms);
    with(combinat):
    F:=fibonacci;
    [seq(F(n),n=0..50)];
    BOUS2(%);
  • Mathematica
    FullSimplify[CoefficientList[Series[(2/Sqrt[5]) * E^(x/2) * (E^(Sqrt[5]/2*x)/2 - E^(-Sqrt[5]/2*x)/2) * (Sin[x]+1) / Cos[x], {x, 0, 20}], x]* Range[0, 20]!] (* Vaclav Kotesovec after Alois P. Heinz, Oct 05 2013 *)
    t[n_, 0] := Fibonacci[n]; t[n_, k_] := t[n, k] = t[n, k-1] + t[n-1, n-k]; a[n_] := t[n, n]; Array[a, 30, 0] (* Jean-François Alcover, Feb 12 2016 *)
  • Python
    from itertools import islice, accumulate
    def A000738_gen(): # generator of terms
        blist, a, b = tuple(), 0, 1
        while True:
            yield (blist := tuple(accumulate(reversed(blist),initial=a)))[-1]
            a, b = b, a+b
    A000738_list = list(islice(A000738_gen(),30)) # Chai Wah Wu, Jun 11 2022

Formula

E.g.f.: (2/sqrt(5)) * exp(x/2) * sinh((sqrt(5)/2)*x) * (sin(x)+1) / cos(x). - Alois P. Heinz, Feb 08 2011
a(n) ~ 4*(exp(sqrt(5)*Pi/2)-1) * (2*n/Pi)^(n+1/2) * exp(Pi/4-n-sqrt(5)*Pi/4) / sqrt(5). - Vaclav Kotesovec, Oct 05 2013
a(n) = sum(A109449(n,k)*A000045(k): k=0..n). - Reinhard Zumkeller, Nov 03 2013

Extensions

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