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A157636
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Triangle read by rows: t(n,m)=1 if m=0 or m=n, otherwise = n*m*(n-m)/2.
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1, 1, 1, 1, 1, 1, 1, 3, 3, 1, 1, 6, 8, 6, 1, 1, 10, 15, 15, 10, 1, 1, 15, 24, 27, 24, 15, 1, 1, 21, 35, 42, 42, 35, 21, 1, 1, 28, 48, 60, 64, 60, 48, 28, 1, 1, 36, 63, 81, 90, 90, 81, 63, 36, 1, 1, 45, 80, 105, 120, 125, 120, 105, 80, 45, 1
(list; table; graph; refs; listen; history; internal format)
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OFFSET
| 0,8
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COMMENTS
| Row sums are 1, 2, 3, 8, 22, 52, 107, 198, 338, 542, 827,... which is 2+n^2*(n^2-1)/12 = 2+A002415(n) if n>0.
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EXAMPLE
| 1;
1, 1;
1, 1, 1;
1, 3, 3, 1;
1, 6, 8, 6, 1;
1, 10, 15, 15, 10, 1;
1, 15, 24, 27, 24, 15, 1;
1, 21, 35, 42, 42, 35, 21, 1;
1, 28, 48, 60, 64, 60, 48, 28, 1;
1, 36, 63, 81, 90, 90, 81, 63, 36, 1;
1, 45, 80, 105, 120, 125, 120, 105, 80, 45, 1;
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MATHEMATICA
| t[n_, m_] = If[n*m*(n - m) == 0, 1, n*m*(n - m)/2];
Table[Table[t[n, m], {m, 0, n}], {n, 0, 10}];
Flatten[%]
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CROSSREFS
| Cf. A107985
Sequence in context: A196989 A034871 A015109 * A086626 A144163 A080858
Adjacent sequences: A157633 A157634 A157635 * A157637 A157638 A157639
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KEYWORD
| nonn,tabl,easy
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AUTHOR
| Roger L. Bagula (rlbagulatftn(AT)yahoo.com), Mar 03 2009
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