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.

A108035 Triangle read by rows: n-th row consists of n copies of the n-th nonzero Fibonacci number.

Original entry on oeis.org

1, 2, 2, 3, 3, 3, 5, 5, 5, 5, 8, 8, 8, 8, 8, 13, 13, 13, 13, 13, 13, 21, 21, 21, 21, 21, 21, 21, 34, 34, 34, 34, 34, 34, 34, 34, 55, 55, 55, 55, 55, 55, 55, 55, 55, 89, 89, 89, 89, 89, 89, 89, 89, 89, 89, 144, 144, 144, 144, 144, 144, 144, 144, 144, 144, 144, 233, 233, 233, 233, 233, 233, 233, 233, 233, 233, 233, 233
Offset: 1

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Author

N. J. A. Sloane, Jun 01 2005

Keywords

Examples

			1; 2,2; 3,3,3; 5,5,5,5; 8,8,8,8,8; ...
		

Crossrefs

Cf. A023607 (row sums).

Programs

  • Haskell
    a108035 n k = a108035_tabl !! (n-1) !! (n-1)
    a108035_row n = a108035_tabl !! (n-1)
    a108035_tabl = zipWith replicate [1..] $ drop 2 a000045_list
    -- Reinhard Zumkeller, Oct 07 2012
    
  • Mathematica
    Flatten[Table[Table[Fibonacci[n],{n-1}],{n,13}]] (* Harvey P. Dale, Jul 18 2015 *)
  • Python
    from math import isqrt
    from sympy import fibonacci
    def A108035(n): return int(fibonacci(1+(m:=isqrt(k:=n<<1))+(k>m*(m+1)))) # Chai Wah Wu, Nov 07 2024

Formula

G.f.: (1+x+y)/((1-x-x^2)*(1-y-y^2)). [U coordinates]

Extensions

Definition clarified by N. J. A. Sloane, Nov 09 2024