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A100440
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Number of distinct values of i*j + j*k + k*i with 1 <= i <= j <= k <= n.
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7
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1, 4, 10, 20, 33, 50, 68, 93, 123, 154, 193, 233, 276, 325, 377, 434, 500, 568, 643, 720, 804, 885, 979, 1068, 1168, 1274, 1381, 1495, 1615, 1746, 1876, 2005, 2148, 2285, 2437, 2596, 2748, 2908, 3077, 3241, 3425, 3608, 3796, 3979, 4181, 4388, 4585, 4804
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OFFSET
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1,2
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COMMENTS
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a(n) <= A000292(n); a(n) = number of terms in n-thh row of the triangle in A200741. - Reinhard Zumkeller, Nov 21 2011
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LINKS
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Table of n, a(n) for n=1..48.
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MAPLE
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f:=proc(n) local i, j, k, t1; t1:={}; for i from 1 to n do for j from i to n do for k from j to n do t1:={op(t1), i*j+j*k+k*i}; od: od: od: t1:=convert(t1, list); nops(t1); end;
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MATHEMATICA
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f[n_] := Length[ Union[ Flatten[ Table[i*j + j*k + k*i, {i, n}, {j, i, n}, {k, j, n}] ]]]; Table[ f[n], {n, 48}] (* Robert G. Wilson v, Dec 14 2004 *)
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PROG
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(Haskell)
a100440 = length . a200741_row -- Reinhard Zumkeller, Nov 21 2011
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CROSSREFS
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Cf. A027430, A100439, A102533, A102534.
Sequence in context: A024986 A028358 A140229 * A027373 A008142 A008045
Adjacent sequences: A100437 A100438 A100439 * A100441 A100442 A100443
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane, Nov 21 2004
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EXTENSIONS
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More terms from Robert G. Wilson v, Dec 14 2004
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STATUS
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approved
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