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Search: id:A051776
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| A051776 |
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Table T(n,m) = Nim-product of n and m, read by antidiagonals, for n >= 1, m >= 1. |
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+0
8
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| 1, 2, 2, 3, 3, 3, 4, 1, 1, 4, 5, 8, 2, 8, 5, 6, 10, 12, 12, 10, 6, 7, 11, 15, 6, 15, 11, 7, 8, 9, 13, 2, 2, 13, 9, 8, 9, 12, 14, 14, 7, 14, 14, 12, 9, 10, 14, 4, 10, 8, 8, 10, 4, 14, 10, 11, 15, 7, 11, 13, 5, 13, 11, 7, 15, 11, 12, 13, 5, 15, 3, 3, 3, 3, 15, 5
(list; table; graph; listen)
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OFFSET
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0,2
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REFERENCES
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J. H. Conway, On Numbers and Games, Academic Press, p. 52.
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LINKS
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Index entries for sequences related to Nim-multiplication
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EXAMPLE
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Table begins:
0 0 0 0 0 0 0 ...
0 1 2 3 4 5 6 ...
0 2 3 1 8 10 11 ...
0 3 1 2 12 15 13 ...
0 4 8 12 6 2 14 ...
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MAPLE
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We continue from A003987: to compute a Nim-multiplication table using (a) an addition table AT := array(0..NA, 0..NA) and (b) a nimsum procedure for larger values; MT := array(0..N, 0..N); for a from 0 to N do MT[a, 0] := 0; MT[0, a] := 0; MT[a, 1] := a; MT[1, a] := a; od: for a from 2 to N do for b from a to N do t1 := {}; for i from 0 to a-1 do for j from 0 to b-1 do u1 := MT[i, b]; u2 := MT[a, j];
if u1<=NA and u2<=NA then u12 := AT[u1, u2]; else u12 := nimsum(u1, u2); fi; u3 := MT[i, j]; if u12<=NA and u3<=NA then u4 := AT[u12, u3]; else u4 := nimsum(u12, u3); fi; t1 := { op(t1), u4}; #t1 := { op(t1), AT[ AT[ MT[i, b], MT[a, j] ], MT[i, j] ] }; od; od;
t2 := sort(convert(t1, list)); j := nops(t2); for i from 1 to nops(t2) do if t2[i] <> i-1 then j := i-1; break; fi; od; MT[a, b] := j; MT[b, a] := j; od; od;
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CROSSREFS
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Cf. A051776, A003987, A051910.
Sequence in context: A157524 A128586 A130971 this_sequence A073734 A062558 A072789
Adjacent sequences: A051773 A051774 A051775 this_sequence A051777 A051778 A051779
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KEYWORD
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tabl,nonn,easy,nice
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), Dec 19 1999
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