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 1-9 of 9 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

Views

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

A083853 Smallest nonnegative integer that can be written as a sum of Fibonacci numbers in n ways, counting 1 twice as Fibonacci number.

Original entry on oeis.org

0, 1, 3, 6, 9, 14, 22, 24, 37, 40, 58, 61, 64, 95, 98, 103, 155, 153, 166, 171, 168, 247, 386, 257, 276, 273, 407, 404, 401, 417, 443, 438, 647, 441, 653, 650, 1011, 705, 674, 708, 1045, 713, 1053, 1048, 1085, 1142, 1051, 1090, 1140, 1153, 1723, 1158, 2661, 1702, 1155, 1710
Offset: 1

Views

Author

R. K. Guy and David W. Wilson, Jun 19 2003

Keywords

Crossrefs

Least inverse of A000121. Cf. A013583.

Formula

A000121(a(n)) = n.

A122195 Numbers that are the sum of exactly 3 sets of Fibonacci numbers.

Original entry on oeis.org

8, 11, 13, 14, 18, 19, 22, 23, 30, 31, 36, 38, 49, 51, 59, 62, 80, 83, 96, 101, 130, 135, 156, 164, 211, 219, 253, 266, 342, 355, 410, 431, 554, 575, 664, 698, 897, 931, 1075, 1130, 1452, 1507, 1740, 1829, 2350, 2439, 2816, 2960, 3803, 3947, 4557, 4790, 6154
Offset: 1

Views

Author

Ron Knott, Aug 25 2006, corrected Aug 29 2006

Keywords

Examples

			8 is the sum of only 3 sets of Fibonacci numbers: {8}, {3,5} and {1,2,5};
11 is the sum of only {3,8}, {1,2,8}, {1,2,3,5}.
		

Crossrefs

Programs

  • GAP
    a:=[11,13,14,18,19,22,23,30];; for n in [9..60] do a[n]:=a[n-4]+a[n-8]+1; od; Concatenation([8], a); # G. C. Greubel, Jul 13 2019
  • Magma
    R:=PowerSeriesRing(Integers(), 60); Coefficients(R!( (8+3*x+2*x^2+x^3-4*x^4-2*x^5+x^6-5*x^8-3*x^9)/(1 - x-x^4+x^5-x^8+x^9) )); // G. C. Greubel, Jul 13 2019
    
  • Maple
    # first N terms:
    series((8+3*x+2*x^2+x^3-4*x^4-2*x^5+x^6-5*x^8-3*x^9)/(x^9-x^8+x^5-x^4-x+1),x,N+1);
  • Mathematica
    CoefficientList[Series[(8+3*x+2*x^2+x^3-4*x^4-2*x^5+x^6-5*x^8-3*x^9)/(1 - x-x^4+x^5-x^8+x^9), {x, 0, 60}], x] (* G. C. Greubel, Jul 13 2019 *)
  • PARI
    my(x='x+O('x^60)); Vec((8+3*x+2*x^2+x^3-4*x^4-2*x^5+x^6-5*x^8 -3*x^9)/(1-x-x^4+x^5-x^8+x^9)) \\ G. C. Greubel, Jul 13 2019
    
  • Sage
    ((8+3*x+2*x^2+x^3-4*x^4-2*x^5+x^6-5*x^8-3*x^9)/(1 - x-x^4+x^5-x^8+x^9)).series(x, 60).coefficients(x, sparse=False) # G. C. Greubel, Jul 13 2019
    

Formula

G.f.: (8+3*x+2*x^2+x^3-4*x^4-2*x^5+x^6-5*x^8-3*x^9)/(1-x-x^4+x^5-x^8+x^9).
a(n) = a(n-4) + a(n-8) + 1.
a(0)=8, a(1)=11, a(2)=13, a(3)=18, then: a(4n) = A022318(n+3) = 2*A000045(n+5) + A000045(n+3) - 1, a(4n+1) = A022406(n+2) = 4*A000045(n+4) - 1, a(4n+2) = A022308(n+4) = 2*A000045(n+4) + A000045(n+6) - 1, a(4n+3) = 3*A000045(n+4) - 1, for n>=1.
a(n) = a(n-1) +a(n-4) -a(n-5) +a(n-8) -a(n-9). - G. C. Greubel, Jul 13 2019

A046815 Smallest number which can be written as the sum of distinct Fibonacci numbers in n ways and such that the Zeckendorf representation of the number uses only even-subscripted Fibonacci numbers.

Original entry on oeis.org

1, 3, 8, 21, 24, 144, 58, 63, 147, 155, 152, 173, 168, 385, 398, 461, 406, 401, 435, 1215, 440, 1016, 1011, 1063, 1053, 1045, 1066, 2608, 1050, 1139, 1160, 2650, 2642, 1155, 2663, 2807, 2647, 6841, 2969, 2749, 2736, 7145, 2757, 2791
Offset: 1

Views

Author

Marjorie Bicknell-Johnson (marjohnson(AT)earthlink.net)

Keywords

Comments

Each term is >= corresponding term of A013583, smallest number that can be written as sum of distinct Fibonacci numbers in n ways. Equality holds for n prime, n a Fibonacci number, n a Lucas number as well as some other cases.

Examples

			a(9)=147 because 147=F(12)+F(4) and 147 is the smallest such integer having 9 representations: 147=144+3 or 144+2+1 or 89+55+3 or 89+55+2+1 or 89+34+21+3 or 89+34+21+2+1 or 89+34+13+8+3 or 89+34+13+8+2+1 or 89+34+13+5+3+2+1.
		

Crossrefs

A122194 Numbers that are the sum of exactly two sets of Fibonacci numbers.

Original entry on oeis.org

3, 5, 6, 9, 10, 15, 17, 25, 28, 41, 46, 67, 75, 109, 122, 177, 198, 287, 321, 465, 520, 753, 842, 1219, 1363, 1973, 2206, 3193, 3570, 5167, 5777, 8361, 9348, 13529, 15126, 21891, 24475, 35421, 39602, 57313, 64078, 92735, 103681, 150049, 167760, 242785
Offset: 1

Views

Author

Ron Knott, Aug 25 2006

Keywords

Examples

			a(1)=3 as 3 is the sum of just 2 Fibonacci sets {3=Fibonacci(4)} and {1=Fibonacci(2), 2=Fibonacci(3)};
a(2)=5 as 5 is sum of Fibonacci sets {5} and {2,3} only.
		

Crossrefs

Programs

  • GAP
    a:= function(n)
        if n mod 2=0 then return 2*Fibonacci(Int((n+6)/2)) -1;
        else return Lucas(1,-1, Int((n+5)/2))[2] -1;
        fi;
      end;
    List([1..50], n-> a(n) ); # G. C. Greubel, Jul 13 2019
  • Magma
    f:=Floor; [(n mod 2) eq 0 select 2*Fibonacci(f((n+6)/2))-1 else Lucas(f((n+5)/2))-1: n in [1..50]]; // G. C. Greubel, Jul 13 2019
    
  • Maple
    fib:= combinat[fibonacci]:
    lucas:=n->fib(n-1)+fib(n+1):
    a:=n -> if n mod 2 = 0 then 2 *fib(n/2+3) -1 else lucas((n+1)/2+2)-1 fi:
    seq(a(n), n=1..50);
  • Mathematica
    LinearRecurrence[{1, 1, -1, 1, -1}, {3, 5, 6, 9, 10, 15}, 40] (* Vincenzo Librandi, Jul 25 2017 *)
    Table[If[Mod[n,2]==0, 2*Fibonacci[(n+6)/2]-1, LucasL[(n+5)/2]-1], {n,50}] (* G. C. Greubel, Jul 13 2019 *)
  • PARI
    vector(50, n, f=fibonacci; if(n%2==0, 2*f((n+6)/2)-1, f((n+7)/2) + f((n+3)/2)-1)) \\ G. C. Greubel, Jul 13 2019
    
  • Sage
    def a(n):
        if (mod(n,2)==0): return 2*fibonacci((n+6)/2) - 1
        else: return lucas_number2((n+5)/2, 1,-1) -1
    [a(n) for n in (1..50)] # G. C. Greubel, Jul 13 2019
    

Formula

a(2n-1) = A000032(n+2) - 1,
a(2n) = 2*A000045(n+3) - 1.
a(2n-1) = A001610(n+2), a(2n) = A001595(n+2).
a(1)=3, a(2)=5, a(3)=6, a(4)=9, a(n) = a(n-2) + a(n-4) + 1, n > 4.
G.f.: (3 + 2*x - 2*x^2 + x^3 - 3*x^4)/(1-x-x^2+x^3-x^4+x^5).
a(n) = A272632(n)-1. - R. J. Mathar, Jan 13 2023

A094607 Rectangular array T by antidiagonals: row n consists of the positive integers k for which there are exactly n sets of Fibonacci numbers whose sum is k.

Original entry on oeis.org

1, 2, 3, 4, 5, 8, 7, 6, 11, 16, 12, 9, 13, 21, 24, 20, 10, 14, 26, 29, 37, 33, 15, 18, 27, 39, 42, 58, 54, 17, 19, 32, 40, 45, 66, 63, 88, 25, 22, 34, 47, 50, 76, 71, 97, 143, 28, 23, 35, 48, 60, 84, 79, 100, 105, 232, 41, 30, 43, 55, 61, 94, 92, 131, 113, 152, 376, 46, 31, 44
Offset: 1

Views

Author

Clark Kimberling, May 14 2004

Keywords

Comments

Row n gives the ranks of n in A000119 after the initial 1 is deleted. Every positive integer occurs exactly once in T; thus a is a permutation of the positive integers. Row 1 is A000071 except for initial terms. Column 1 is A013583.

Examples

			A northwest corner of T:
1 2 4 7 12
3 5 6 9 10
8 11 13 14 18
16 21 26 27 32
6 is in row 2 because there are exactly 2 sets of Fibonacci
numbers whose sum is 6. They are {1,5} and {1,2,3}.
		

Crossrefs

A347349 a(n) is the smallest positive integer which can be represented as the sum of distinct Lucas numbers (A000032) in exactly n ways.

Original entry on oeis.org

1, 3, 7, 14, 21, 32, 50, 54, 83, 90, 130, 137, 144, 213, 220, 231, 347, 343, 372, 383, 376, 553, 864, 575, 618, 611, 911, 904, 897, 933, 991, 980, 1447, 987, 1461, 1454, 2261, 1577, 1508, 1584, 2337, 1595, 2355, 2344, 2427, 2554, 2351, 2438, 2550, 2579, 3853, 2590, 5951, 3806, 2583
Offset: 1

Views

Author

Ilya Gutkovskiy, Dec 19 2021

Keywords

Crossrefs

A359391 a(n) is the smallest number which can be represented as the sum of n distinct positive Fibonacci numbers (1 is allowed twice as a part) in exactly n ways, or -1 if no such number exists.

Original entry on oeis.org

1, 2, 3, 16, 27, 71, 116, 278, 451, 818, 1305, 2169, 3925, 8119, 13117, 23252, 37858, 62999, 101939, 178088, 298357, 484576, 813710, 1613509, 2610739, 4224275, 6845969, 11280196, 19772533, 32524576, 53157802, 85936132
Offset: 0

Views

Author

Ilya Gutkovskiy, Dec 29 2022

Keywords

Examples

			For n = 3: 16 = Fibonacci(1) + Fibonacci(3) + Fibonacci(7) =
                Fibonacci(2) + Fibonacci(3) + Fibonacci(7) =
                Fibonacci(4) + Fibonacci(5) + Fibonacci(6) =
                1 + 2 + 13 =
                1'+ 2 + 13 =
                3 + 5 + 8.
		

Crossrefs

Extensions

a(0), a(10)-a(18) from Alois P. Heinz, Dec 29 2022
a(19)-a(31) from David A. Corneth, Dec 30 2022

A359631 a(n) is the smallest positive integer which can be represented as the sum of distinct positive Fibonacci n-step numbers (with a single type of 1) in exactly n ways, or -1 if no such integer exists.

Original entry on oeis.org

1, 3, 44, 416, 26815, 464031
Offset: 1

Views

Author

Ilya Gutkovskiy, Jan 08 2023

Keywords

Examples

			For n = 2: 3 = Fibonacci(4) = 3 = Fibonacci(2) + Fibonacci(3) = 1 + 2.
		

Crossrefs

Showing 1-9 of 9 results.