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Search: id:A128716
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| A128716 |
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Triangle where the n-th row, of n terms in order, contains consecutive multiples of n. The smallest term of row n is the smallest integer >= the largest term of row (n-1), for n >= 2. |
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1
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| 1, 2, 4, 6, 9, 12, 12, 16, 20, 24, 25, 30, 35, 40, 45, 48, 54, 60, 66, 72, 78, 84, 91, 98, 105, 112, 119, 126, 128, 136, 144, 152, 160, 168, 176, 184, 189, 198, 207, 216, 225, 234, 243, 252, 261, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 363, 374, 385, 396
(list; table; graph; listen)
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OFFSET
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1,2
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COMMENT
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If we instead had the triangle where the smallest term of row n is the smallest integer strictly > the largest term of row (n-1), for n >= 2, then we would have sequence A033291.
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FORMULA
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T(n,k+1)=T(n,k)+n for 1<=k<n. T(n,1)=n*ceil[T(n-1,n-1)/n] for n>=2. - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Nov 01 2007
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EXAMPLE
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Triangle starts
1;
2, 4;
6, 9, 12;
12, 16, 20, 24;
25, 30, 35, 40, 45;
48, 54, 60, 66, 72, 78;
84, 91, 98,105,112,119,126;
128,136,144,152,160,168,176,184;
189,198,207,216,225,234,243,252,261;
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MAPLE
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A128716 := proc(n, k) option remember ; if n = 1 then 1 ; elif k = 1 then n*ceil(A128716(n-1, n-1)/n) ; else A128716(n, k-1)+n ; fi ; end: for n from 1 to 11 do for k from 1 to n do printf("%d, ", A128716(n, k)) ; od: od: - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Nov 01 2007
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CROSSREFS
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Cf. A033291.
Adjacent sequences: A128713 A128714 A128715 this_sequence A128717 A128718 A128719
Sequence in context: A054519 A038107 A077220 this_sequence A025057 A030763 A143145
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KEYWORD
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easy,nonn,tabl
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AUTHOR
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Leroy Quet (qq-quet(AT)mindspring.com), Jun 12 2007
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EXTENSIONS
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More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Nov 01 2007
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