

A241522


The number of Ppositions in the game of Nim with up to 4 piles, allowing for piles of zero, such that the number of objects in each pile does not exceed n.


5



1, 8, 21, 64, 89, 168, 301, 512, 561, 712, 965, 1344, 1801, 2408, 3165, 4096, 4193, 4488, 4981, 5696, 6585, 7720, 9101, 10752, 12433, 14408, 16677, 19264, 22121, 25320, 28861, 32768, 32961, 33544, 34517, 35904, 37657, 39848, 42477, 45568, 48881, 52680, 56965, 61760, 67017
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OFFSET

0,2


COMMENTS

Ppositions in the game of Nim are tuples of numbers with a NimSum equal to zero. (0,1,1,0) is considered different from (1,0,1,0).


LINKS



FORMULA

If b = floor(log_2(n)) is the number of digits in the binary representation of n and c = n + 1  2^b, then a(n) = 2^(3*b) + 6*c^2*2^b + a(c1).
a(2^n1) = 2^(3*n).


EXAMPLE

If the largest number is 1, then there should be an even number of piles of size 1. Thus, a(1)=8.


MATHEMATICA

Table[Length[Select[Flatten[Table[{n, k, j, BitXor[n, k, j]}, {n, 0, a}, {k, 0, a}, {j, 0, a}], 2], #[[4]] <= a &]], {a, 0, 50}]


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



