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.

A000119 Number of representations of n as a sum of distinct Fibonacci numbers.

Original entry on oeis.org

1, 1, 1, 2, 1, 2, 2, 1, 3, 2, 2, 3, 1, 3, 3, 2, 4, 2, 3, 3, 1, 4, 3, 3, 5, 2, 4, 4, 2, 5, 3, 3, 4, 1, 4, 4, 3, 6, 3, 5, 5, 2, 6, 4, 4, 6, 2, 5, 5, 3, 6, 3, 4, 4, 1, 5, 4, 4, 7, 3, 6, 6, 3, 8, 5, 5, 7, 2, 6, 6, 4, 8, 4, 6, 6, 2, 7, 5, 5, 8, 3, 6, 6, 3, 7, 4, 4, 5, 1, 5, 5, 4, 8, 4, 7, 7, 3, 9, 6, 6, 9, 3, 8, 8, 5
Offset: 0

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Keywords

Comments

Number of partitions into distinct Fibonacci parts (1 counted as single Fibonacci number).
Inverse Euler transform of sequence has generating function Sum_{n>1} (x^F(n) - x^(2*F(n))) where F() are the Fibonacci numbers.
a(n) = 1 if and only if n+1 is a Fibonacci number. The length of such a quasi-period (from Fib(i)-1 to Fib(i+1)-1, inclusive) is a Fibonacci number + 1. The maximum value of a(n) within each subsequent quasi-period increases by a Fibonacci number. For example, from n = 143 to n = 232, the maximum is 13. From 232 to 376, the maximum is 16, an increase of 3. From 376 to 609, 21, an increase of 5. From 609 to 986, 26, increasing by 5 again. Each two subsequent maxima seem to increase by the same increment, the next Fibonacci number. - Kerry Mitchell, Nov 14 2009
The maxima of the quasi-periods are in A096748. - Max Barrentine, Sep 13 2015
Stockmeyer proves that a(n) <= sqrt(n+1) with equality iff n = Fibonacci(m)^2 - 1 for some m >= 2 (cf. A080097). - Michel Marcus, Mar 02 2016

References

  • M. Bicknell-Johnson, pp. 53-60 in "Applications of Fibonacci Numbers", volume 8, ed: F. T. Howard, Kluwer (1999); see Theorem 3.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Cf. A007000, A003107, A000121, A080097, A096748. Least inverse is A013583.

Programs

  • Haskell
    a000119 = p $ drop 2 a000045_list where
       p _      0 = 1
       p (f:fs) m = if m < f then 0 else p fs (m - f) + p fs m
    -- Reinhard Zumkeller, Dec 28 2012, Oct 21 2011
  • Maple
    with(combinat): p := product((1+x^fibonacci(i)), i=2..25): s := series(p,x,1000): for k from 0 to 250 do printf(`%d,`,coeff(s,x,k)) od: # James Sellers, May 29 2000
  • Mathematica
    CoefficientList[ Normal@Series[ Product[ 1+z^Fibonacci[ k ], {k, 2, 13} ], {z, 0, 233} ], z ]
    nmax = 104; s = Union@Table[Fibonacci[n], {n, nmax}];
    Table[Length@Select[IntegerPartitions[n, All, s], DeleteDuplicates[#] == # &], {n, 0, nmax}] (* Robert Price, Aug 17 2020 *)
  • PARI
    a(n)=local(A,m,f); if(n<0,0,A=1+x*O(x^n); m=2; while((f=fibonacci(m))<=n,A*=1+x^f; m++); polcoeff(A,n))
    
  • PARI
    f(x,y,z)=if(xCharles R Greathouse IV, Dec 14 2015
    

Formula

a(A000045(n)) = A065033(n).
a(n) = (1/n)*Sum_{k=1..n} b(k)*a(n-k), b(k) = Sum_{f} (-1)^(k/f+1)*f, where the last sum is taken over all Fibonacci numbers f dividing k. - Vladeta Jovovic, Aug 28 2002
a(n) = 1, if n <= 2; a(n) = a(Fibonacci(i-2)+k)+a(k) if n>2 and 0<=k2 and Fibonacci(i-3)<=kA000045) <= n and k=n-Fibonacci(i). [Bicknell-Johnson] - Ron Knott, Dec 06 2004
a(n) = f(n,1,1) with f(x,y,z) = if xReinhard Zumkeller, Nov 11 2009
G.f.: Product_{n>=1} 1 + q^F(n+1) = 1 + Sum_{n>=1} ( q^F(n+1) * Product_{k=1..n-1} 1 + q^F(k+1) ). - Joerg Arndt, Oct 20 2012
a(A000071(n)) = 1. - Reinhard Zumkeller, Dec 28 2012

Extensions

More terms from James Sellers, May 29 2000

A127218 Half-indexed Lucas numbers second version L(n)=A000032=Lucas numbers a(0)=2, a(1)=2, a(2)=1, a(3)=2, a(4)=3, a(5)=3, a(2n)=L(n), for n>2: a(2n+1)=L(n)+L(n-3)=2*L(n-1) for n>5: a(n)+a(n+2)=a(n+4) a(2n)=L(n), so a(n)=L(n/2).

Original entry on oeis.org

2, 2, 1, 2, 3, 3, 4, 6, 7, 8, 11, 14, 18, 22, 29, 36, 47, 58, 76, 94, 123, 152, 199, 246, 322, 398, 521, 644, 843, 1042, 1364, 1686, 2207, 2728, 3571, 4414, 5778, 7142, 9349, 11556, 15127, 18698, 24476, 30254, 39603, 48952, 64079
Offset: 0

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Author

Miklos Kristof, Mar 28 2007

Keywords

Comments

b(n)=A096748(n-1): for n>5: b(n)+b(n+4)=a(n+2) for n>5: a(n)+a(n+4)=5*b(n+2).

Crossrefs

Programs

  • Maple
    b[0]:=2:b[1]:=1:for n from 2 to 80 do b[n]:=b[n-1]+b[n-2] od: a[0]:=2:a[1]:=2:a[2]:=1:a[3]:=2:a[4]:=3:a[5]:=3: for n from 3 to 39 do a[2*n]:=b[n]:a[2*n+1]:=b[n]+b[n-3] od: seq(a[n],n=0..79);
  • Mathematica
    LinearRecurrence[{0,1,0,1},{2,2,1,2,3,3,4,6,7,8},60] (* Harvey P. Dale, Jun 22 2022 *)
  • PARI
    Vec((1 + x)*(2 - x^2 + x^3 - x^4 + x^7 - x^8) / (1 - x^2 - x^4) + O(x^45)) \\ Colin Barker, Aug 03 2020

Formula

From Colin Barker, Aug 03 2020: (Start)
G.f.: (1 + x)*(2 - x^2 + x^3 - x^4 + x^7 - x^8) / (1 - x^2 - x^4).
a(n) = a(n-2) + a(n-4) for n>10.
(End)

A226649 Fibonacci shuffles: a(2n) = A000071(n) and a(2n+1) = A001611(n+2).

Original entry on oeis.org

0, 2, 0, 3, 1, 4, 2, 6, 4, 9, 7, 14, 12, 22, 20, 35, 33, 56, 54, 90, 88, 145, 143, 234, 232, 378, 376, 611, 609, 988, 986, 1598, 1596, 2585, 2583, 4182, 4180, 6766, 6764, 10947, 10945, 17712, 17710, 28658, 28656, 46369, 46367, 75026, 75024, 121394, 121392, 196419, 196417, 317812, 317810
Offset: 0

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Author

V. T. Jayabalaji, Jun 14 2013

Keywords

Comments

a(2*n+1) = a(2*n) + A157725(n); a(2*n) = a(2*n-1) - 2 for n > 0. - Reinhard Zumkeller, Jul 30 2013

Crossrefs

Programs

  • Haskell
    import Data.List (transpose)
    a226649 n = a226649_list !! n
    a226649_list = concat $ transpose [a000071_list, drop 2 a001611_list]
    -- Reinhard Zumkeller, Jul 30 2013
  • Mathematica
    LinearRecurrence[{-1,1,1,1,1},{0,2,0,3,1},60] (* Harvey P. Dale, Sep 12 2018 *)

Formula

G.f. -x*(2+x^2+2*x^3+2*x) / ( (1+x)*(x^4+x^2-1) ). - R. J. Mathar, Jul 15 2013
a(n) + a(n+1) = A096748(n+2). - R. J. Mathar, Jul 15 2013
a(2n-1) - 1 = a(2n) + 1 = fib(n+1) = A000045(n+1) for n > 0. - T. D. Noe, Jul 23 2013

A227356 Partial sums of A129361.

Original entry on oeis.org

1, 2, 5, 10, 20, 36, 65, 112, 193, 324, 544, 900, 1489, 2442, 4005, 6534, 10660, 17336, 28193, 45760, 74273, 120408, 195200, 316216, 512257, 829458, 1343077, 2174130, 3519412, 5696124, 9219105, 14919408, 24144289
Offset: 1

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Author

Kival Ngaokrajang, Jul 08 2013

Keywords

Comments

Sum of labeled numbers of boxes arranged as Pyramid type-II with base Fibonacci(n).
Let us call a Pyramid "type-I" when each row starts with the same number as the leftmost base number, and "type-II" when each column has the same number as the base.
The Pyramid arrangements are related to other sequences as follows:
Base Number Type-I Type-II
----------- ------ -------
Natural A002623 A034828
Fibonacci A129696 a(n)
1,0 A008805
See illustration in links.

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{2,1,-3,1,-1,0,1},{1,2,5,10,20,36,65},40] (* Harvey P. Dale, Jun 30 2025 *)

Formula

For n >=2, a(n) = a(n-1) + A129361(n-1).
G.f. -x*(1+x)*(x^2-x+1) / ( (x-1)*(x^2+x-1)*(x^4+x^2-1) ). - Joerg Arndt, Jul 10 2013
a(n) = 2 + A000045(n+4) - A096748(n+6). - R. J. Mathar, Jul 20 2013
Showing 1-4 of 4 results.