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 1-8 of 8 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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Author

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

A003107 Number of partitions of n into Fibonacci parts (with a single type of 1).

Original entry on oeis.org

1, 1, 2, 3, 4, 6, 8, 10, 14, 17, 22, 27, 33, 41, 49, 59, 71, 83, 99, 115, 134, 157, 180, 208, 239, 272, 312, 353, 400, 453, 509, 573, 642, 717, 803, 892, 993, 1102, 1219, 1350, 1489, 1640, 1808, 1983, 2178, 2386, 2609, 2854, 3113, 3393, 3697, 4017, 4367, 4737
Offset: 0

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Keywords

Comments

The partitions allow repeated items but the order of items is immaterial (1+2=2+1). - Ron Knott, Oct 22 2003
A098641(n) = a(A000045(n)). - Reinhard Zumkeller, Apr 24 2005

Examples

			a(4) = 4 since the 4 partitions of 4 using only Fibonacci numbers, repetitions allowed, are 1+1+1+1, 2+2, 2+1+1, 3+1.
		

References

  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Cf. A007000, A005092, A028290 (where the only Fibonacci numbers allowed are 1, 2, 3, 5 and 8).
Row sums of A319394.

Programs

  • Haskell
    import Data.MemoCombinators (memo2, integral)
    a003107 n = a003107_list !! n
    a003107_list = map (p' 2) [0..] where
       p' = memo2 integral integral p
       p _ 0 = 1
       p k m | m < fib   = 0
             | otherwise = p' k (m - fib) + p' (k + 1) m where fib = a000045 k
    -- Reinhard Zumkeller, Dec 09 2015
    
  • Maple
    F:= combinat[fibonacci]:
    b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<2, 0,
           b(n, i-1)+`if`(F(i)>n, 0, b(n-F(i), i))))
        end:
    a:= proc(n) local j; for j from ilog[(1+sqrt(5))/2](n+1)
           while F(j+1)<=n do od; b(n, j)
        end:
    seq(a(n), n=0..100);  # Alois P. Heinz, Jul 11 2013
  • Mathematica
    CoefficientList[ Series[1/ Product[1 - x^Fibonacci[i], {i, 2, 21}], {x, 0, 53}], x] (* Robert G. Wilson v, Mar 28 2006 *)
    nmax = 53;
    s = Table[Fibonacci[n], {n, nmax}];
    Table[Count[IntegerPartitions@n, x_ /; SubsetQ[s, x]], {n, 0, nmax}] (* Robert Price, Jul 31 2020 *)
    F = Fibonacci;
    b[n_, i_] := b[n, i] = If[n == 0, 1, If[i < 2, 0,
         b[n, i - 1] + If[F[i] > n, 0, b[n - F[i], i]]]];
    a[n_] := Module[{j}, For[j = Floor@Log[(1+Sqrt[5])/2, n+1],
         F[j + 1] <= n, j++]; b[n, j]];
    a /@ Range[0, 100] (* Jean-François Alcover, May 21 2021, after Alois P. Heinz *)
  • PARI
    f(x,y,z)=if(xCharles R Greathouse IV, Dec 14 2015

Formula

a(n) = (1/n)*Sum_{k=1..n} A005092(k)*a(n-k), n > 1, a(0)=1. - Vladeta Jovovic, Jan 21 2002
G.f.: Product_{i>=2} 1/(1-x^fibonacci(i)). - Ron Knott, Oct 22 2003
a(n) = f(n,1,1) with f(x,y,z) = if xReinhard Zumkeller, Nov 11 2009
G.f.: 1 + Sum_{i>=2} x^Fibonacci(i) / Product_{j=2..i} (1 - x^Fibonacci(j)). - Ilya Gutkovskiy, May 07 2017

Extensions

More terms from Vladeta Jovovic, Jan 21 2002

A290807 Number of partitions of n into Pell parts (A000129).

Original entry on oeis.org

1, 1, 2, 2, 3, 4, 5, 6, 7, 8, 10, 11, 14, 15, 18, 20, 23, 26, 29, 32, 36, 39, 44, 47, 53, 57, 63, 68, 74, 81, 88, 95, 103, 110, 120, 128, 139, 148, 159, 170, 182, 195, 208, 221, 236, 250, 267, 282, 300, 317, 336, 355, 375, 396, 418, 440, 464, 487, 514, 539, 568, 595, 625, 655, 687, 720, 754, 788
Offset: 0

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Author

Ilya Gutkovskiy, Aug 11 2017

Keywords

Examples

			a(5) = 4 because we have [5], [2, 2, 1], [2, 1, 1, 1] and [1, 1, 1, 1, 1].
		

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[Product[1/(1 - x^Fibonacci[k, 2]), {k, 1, 15}], {x, 0, 67}], x]

Formula

G.f.: Product_{k>=1} 1/(1 - x^A000129(k)).

A357380 Expansion of Product_{k>=1} (1 - x^Fibonacci(k)).

Original entry on oeis.org

1, -2, 0, 1, 1, -1, 0, 1, -2, 1, 0, 1, -2, 0, 2, -1, 0, 0, 1, -2, 0, 1, 1, 0, -2, 1, 0, 0, 0, 1, -2, 0, 1, 1, -1, 0, 1, -1, -1, 0, 2, -1, 0, 0, 0, 0, 0, 1, -2, 0, 1, 1, -1, 0, 1, -2, 1, 0, 1, -2, 1, 0, -1, 1, 1, 0, -2, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, -2, 0, 1, 1, -1, 0, 1, -2, 1, 0, 1, -2, 0, 2, -1, 0, 0, 1, -2, 0, 2, -1, 0, -1
Offset: 0

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Author

Ilya Gutkovskiy, Sep 26 2022

Keywords

Comments

Convolution inverse of A007000.
First differences of A093996.

Crossrefs

Programs

  • Mathematica
    nmax = 100; CoefficientList[Series[Product[(1 - x^Fibonacci[k]), {k, 1, 21}], {x, 0, nmax}], x]

A280168 Expansion of Product_{k>=2} 1/(1 - x^(Fibonacci(k)^2)).

Original entry on oeis.org

1, 1, 1, 1, 2, 2, 2, 2, 3, 4, 4, 4, 5, 6, 6, 6, 7, 8, 9, 9, 10, 11, 12, 12, 13, 15, 16, 17, 18, 20, 21, 22, 23, 25, 27, 28, 30, 32, 34, 35, 37, 39, 41, 43, 45, 48, 50, 52, 54, 57, 60, 62, 65, 68, 72, 74, 77, 80, 84, 87, 90, 94, 98, 102, 106, 110, 114, 118, 123, 127, 132, 136, 142, 147, 152, 157, 163, 169, 174, 180, 186, 193, 199
Offset: 0

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Author

Ilya Gutkovskiy, Dec 27 2016

Keywords

Comments

Number of partitions of n into squares of Fibonacci numbers (with a single type of 1).

Examples

			a(8) = 3 because we have [4, 4], [4, 1, 1, 1, 1] and [1, 1, 1, 1, 1, 1, 1, 1].
		

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[Product[1/(1 - x^Fibonacci[k]^2), {k, 2, 20}], {x, 0, 82}], x]

Formula

G.f.: Product_{k>=2} 1/(1 - x^(Fibonacci(k)^2)).

A356928 a(n) is the number of solutions, j >= 0 and 1 <= m_1 <= ... <= m_n, of the equation Sum_{k=1..n} F(m_k) = 2^j where F(i) is the i-th Fibonacci number.

Original entry on oeis.org

0, 4, 9, 15, 60, 106
Offset: 0

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Author

Pagdame Tiebekabe, Sep 05 2022

Keywords

Comments

a(6) >= 298. We do not have information about whether 298 has been proved to be a(6). - Peter Munn, Sep 08 2022
a(7) >= 772. - Jon E. Schoenfield, Sep 05 2022

Examples

			For n=2, the a(2) = 9 solutions are 1 with (1,1), 1 with (1,2), 2 with (1,4), 1 with (2,2), 2 with (2,4), 2 with (3,3), 3 with (4,5), 4 with (4,7), and 4 with (6,6) according to the paper of Bravo and Luca. [That is, 2=1+1, 2=1+1 (again), 4=1+3, 2=1+1 (again), 4=1+3 (again), 4=2+2, 8=3+5, 16=3+13, and 16=8+8.]
		

References

  • J. J. Bravo, and F. Luca, On the Diophantine equation F_n+F_m=2^a, Quaest. Math. 39 (2016) 391-400.
  • P. Tiebekabe and I. Diouf, On solutions of Diophantine equation F_{n_1}+F_{n_2}+F_{n_3}+F_{n_4}=2^a, Journal of Algebra and Related Topics, Volume 9, Issue 2 (2021), 131-148.

Crossrefs

Cf. A007000.

Extensions

a(0)=0 added by Peter Munn, Sep 05 2022
Name and example edited by Peter Munn, Sep 06 2022

A288122 Number of partitions of n into prime Fibonacci numbers (A005478).

Original entry on oeis.org

1, 0, 1, 1, 1, 2, 2, 2, 3, 3, 4, 4, 5, 6, 6, 8, 8, 9, 11, 11, 13, 14, 15, 17, 18, 20, 22, 23, 26, 27, 30, 32, 34, 37, 39, 42, 45, 47, 51, 54, 57, 61, 64, 68, 72, 76, 80, 84, 89, 93, 98, 103, 108, 113, 119, 124, 130, 136, 142, 148, 155, 161, 168, 175, 182, 190, 197, 205, 213, 221, 230
Offset: 0

Views

Author

Ilya Gutkovskiy, Jun 05 2017

Keywords

Examples

			a(8) = 3 because we have [5, 3], [3, 3, 2] and [2, 2, 2, 2].
		

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[Product[1/(1 - Boole[PrimeQ[Fibonacci[k]]] x^Fibonacci[k]), {k, 1, 30}], {x, 0, 70}], x]

Formula

G.f.: Product_{k>=1} 1/(1 - x^A005478(k)).

A350240 Number of representations of n as a sum of distinct Fibonacci numbers where 1 can be included twice.

Original entry on oeis.org

1, 1, 2, 2, 2, 3, 2, 3, 3, 3, 4, 3, 3, 4, 3, 5, 4, 4, 5, 3, 4, 4, 4, 6, 5, 5, 6, 4, 6, 5, 5, 6, 4, 4, 5, 4, 7, 6, 6, 8, 5, 7, 6, 6, 8, 6, 6, 7, 5, 8, 6, 6, 7, 4, 5, 5, 5, 8, 7, 7, 9, 6, 9, 8, 8, 10, 7, 7, 8, 6, 10, 8, 8, 10, 6, 8, 7, 7, 10, 8, 8, 9, 6
Offset: 0

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Author

Kung Yue Tong, Dec 21 2021

Keywords

Comments

A part of size 1 can be included twice in the partitions enumerated by this sequence, but there is only 1 way to include it once. The sequence A000119 only allows 1 to be included once and A000121 allows it to be included twice, but it in two different ways once.
Some connections with the upper Wythoff sequence (A001950):
a(n) = A000121(n) for n in A001950.
a(n) = A000119(n) for n-1 in A001950.
a(n) = A000121(n) - A000119(n) for n+1 in A001950.

Examples

			The a(10)=4 partitions are: 8+2 = 8+1+1 = 5+3+1+1 = 5+3+2.
The a(11)=3 partitions are: 8+3 = 8+2+1 = 5+3+2+1.
The a(12)=3 partitions are: 8+3+1 = 8+2+1+1 = 5+3+2+1+1.
		

Crossrefs

Programs

  • PARI
    seq(n)=my(m=2); while(fibonacci(m)Andrew Howroyd, Dec 21 2021

Formula

G.f.: (1 + x + x^2)*Product_{k>=3} (1 + x^Fibonacci(k)). - Andrew Howroyd, Dec 21 2021
Showing 1-8 of 8 results.