OFFSET
0,12
COMMENTS
Note the Zeckendorf representation of 0 is taken to be the empty sum.
The Wythoff array A035513 is the subtable formed by rows 3, 11, 16, 24, 32, ... (A035337). If, instead, we use rows 2, 7, 10, 15, 20, ... (A035336) or 1, 4, 6, 9, 12, ... (A003622), we get the Wythoff array extended by 1 column (A287869) or 2 columns (A287870) respectively.
Similarly, using A035338 truncates by 1 column; and in general if S_k is column k of the Wythoff array then the rows here numbered by S_k form an array A_k that starts with column k-2 of the Wythoff array. (A_0 and A_1 are the 2 extended arrays mentioned above.) As every positive integer occurs exactly once in the Wythoff array, every row except row 0 of A(.,.) is a row of exactly one such A_k.
Columns 4 onwards match certain columns of the multiplication table for Knuth's Fibonacci (or circle) product (extended variant - see A135090 and formula below).
LINKS
Encyclopedia of Mathematics, Zeckendorf representation
FORMULA
EXAMPLE
Example for n = 4, k = 3. The Zeckendorf representation of 4 is F_4 + F_2 = 3 + 1. So the values of i in the sums in the definition are 4 and 2; hence A(4,3) = Sum_{i = 2,4} F_{i+k-2} = F_{4+3-2} + F_{2+3-2} = F_5 + F_3 = 5 + 2 = 7.
Square array A(n,k) begins:
n\k| 0 1 2 3 4 5 6
----+--------------------------------
0 | 0 0 0 0 0 0 0 ...
1* | 0 1 1 2 3 5 8 ...
2 | 1 1 2 3 5 8 13 ...
3 | 1 2 3 5 8 13 21 ...
4* | 1 3 4 7 11 18 29 ...
5 | 2 3 5 8 13 21 34 ...
6* | 2 4 6 10 16 26 42 ...
7 | 3 4 7 11 18 29 47 ...
8 | 3 5 8 13 21 34 55 ...
9* | 3 6 9 15 24 39 63 ...
10 | 4 6 10 16 26 42 68 ...
11 | 4 7 11 18 29 47 76 ...
12* | 4 8 12 20 32 52 84 ...
...
The asterisked rows form the start of the extended Wythoff array (A287870).
PROG
(PARI)
A5206(m) = if(m>0, m-A5206(A5206(m-1)), 0)
A(n, k) = if(k==2, n, if(k==1, A5206(n), if(k==0, n-A5206(n), A(n, k-2)+A(n, k-1)))) \\ simple encoding of formulas, not efficient
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Peter Munn, Sep 23 2022
STATUS
approved