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.

A007000 Number of partitions of n into Fibonacci parts (with 2 types of 1).

Original entry on oeis.org

1, 2, 4, 7, 11, 17, 25, 35, 49, 66, 88, 115, 148, 189, 238, 297, 368, 451, 550, 665, 799, 956, 1136, 1344, 1583, 1855, 2167, 2520, 2920, 3373, 3882, 4455, 5097, 5814, 6617, 7509, 8502, 9604, 10823, 12173, 13662, 15302, 17110, 19093, 21271, 23657, 26266
Offset: 0

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Examples

			a(2)=4 because we have [2],[1',1'],[1',1],[1,1] (the two types of 1 are denoted 1 and 1').
		

References

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

Crossrefs

Cf. A003107.
Cf. A000045.

Programs

  • Haskell
    import Data.MemoCombinators (memo2, integral)
    a007000 n = a007000_list !! n
    a007000_list = map (p' 1) [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
    with(combinat): gf := 1/product((1-q^fibonacci(k)), k=1..20): s := series(gf, q, 200): for i from 0 to 199 do printf(`%d,`,coeff(s, q, i)) od: # James Sellers, Feb 08 2002
  • Mathematica
    CoefficientList[ Series[ 1/Product[1 - x^Fibonacci[i], {i, 1, 15}], {x, 0, 50}], x]
    nmax = 46; f = Table[Fibonacci[n], {n, nmax}];
    Table[Length[IntegerPartitions[n, All, f]], {n, 0, nmax}] (* Robert Price, Aug 02 2020 *)

Formula

a(n) = 1/n*Sum_{k=1..n} (A005092(k)+1)*a(n-k), n > 1, a(0)=1. - Vladeta Jovovic, Aug 22 2002
G.f.: 1/Product_{j>=1} (1-x^fibonacci(j)). - Emeric Deutsch, Mar 05 2006
G.f.: Sum_{i>=0} x^Fibonacci(i) / Product_{j=1..i} (1 - x^Fibonacci(j)). - Ilya Gutkovskiy, May 07 2017

Extensions

More terms from James Sellers, Feb 08 2002