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.

A000121 Number of representations of n as a sum of Fibonacci numbers (1 is allowed twice as a part).

Original entry on oeis.org

1, 2, 2, 3, 3, 3, 4, 3, 4, 5, 4, 5, 4, 4, 6, 5, 6, 6, 5, 6, 4, 5, 7, 6, 8, 7, 6, 8, 6, 7, 8, 6, 7, 5, 5, 8, 7, 9, 9, 8, 10, 7, 8, 10, 8, 10, 8, 7, 10, 8, 9, 9, 7, 8, 5, 6, 9, 8, 11, 10, 9, 12, 9, 11, 13, 10, 12, 9, 8, 12, 10, 12, 12, 10, 12, 8, 9, 12, 10, 13, 11, 9, 12, 9, 10, 11, 8, 9, 6, 6, 10, 9
Offset: 0

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Author

Keywords

Comments

Number of partitions into distinct Fibonacci parts (1 counted as two distinct Fibonacci numbers).
Inverse Euler transform of sequence has generating function sum_{n>0} x^F(n)-x^{2F(n)} where F() is Fibonacci.

References

  • 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

Least inverse is A083853.

Programs

  • Maple
    with(combinat): p := product((1+x^fibonacci(i)), i=1..25): s := series(p,x,1000): for k from 0 to 250 do printf(`%d,`,coeff(s,x,k)) od:
  • Mathematica
    imax = 20; p = Product[1+x^Fibonacci[i], {i, 1, imax}]; CoefficientList[p, x][[1 ;; Fibonacci[imax]+1]] (* Jean-François Alcover, Feb 04 2016, adapted from Maple *)
    nmax = 91; s=Total/@Subsets[Select[Table[Fibonacci[i], {i, nmax}], # <= nmax &]];
    Table[Count[s, n], {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=1; while((f=fibonacci(m))<=n,A*=1+x^f; m++); polcoeff(A,n))

Formula

a(0) = 1; for n >= 1, a(n) = A000119(n) + A000119(n-1). - Peter Munn, Jan 19 2018

Extensions

More terms from James Sellers, Jun 18 2000

A013583 Smallest positive number that can be written as sum of distinct Fibonacci numbers in n ways.

Original entry on oeis.org

1, 3, 8, 16, 24, 37, 58, 63, 97, 105, 152, 160, 168, 249, 257, 270, 406, 401, 435, 448, 440, 647, 1011, 673, 723, 715, 1066, 1058, 1050, 1092, 1160, 1147, 1694, 1155, 1710, 1702, 2647, 1846, 1765, 1854, 2736, 1867, 2757, 2744, 2841, 2990, 2752, 2854, 2985, 3019, 4511, 3032, 6967, 4456, 3024, 4477, 4616, 4451, 7349, 4629, 7218, 4917, 4621, 4854, 4904, 7179, 7166, 4896, 7200, 7247, 7310, 7213, 7831, 8187, 7488, 7205, 11614, 7480, 7815, 7857, 7925, 11593, 18154, 7912, 11813, 11682, 11653
Offset: 1

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Author

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

Keywords

Comments

Smallest nonnegative number that can be written as sum of distinct Fibonacci numbers in n ways would be the same, except starting with 0.

Examples

			1 = 1; 3 = 3 = 2 + 1; 8 = 8 = 5 + 3 = 5 + 2 + 1.
		

Crossrefs

Least inverse of A000119. Cf. A046815, A083853.

Formula

A000119(a(n)) = n (for n>1).

Extensions

Additional terms from Jeffrey Shallit
Extended to 600 terms by Daniel C. Fielder
Entries rechecked by David W. Wilson, Jun 18 2003

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

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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

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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
Showing 1-4 of 4 results.