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Search: id:A132278
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| A132278 |
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Number of distinct terms in rows 1 through n of the triangle of the Narayana numbers (A001263). |
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+0
1
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| 1, 1, 2, 3, 5, 7, 10, 13, 17, 21, 26, 31, 37, 43, 49, 56, 64, 72, 81, 90, 100, 110, 121, 132, 144, 156, 169, 182, 196, 210, 225, 240, 256, 272, 289, 306, 324, 342, 361, 380, 400, 420, 441, 462, 484, 506, 529, 552, 575, 599, 624, 649, 675, 701, 728, 755, 783
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OFFSET
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1,3
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EXAMPLE
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a(6)=7 because there are 7 distinct terms in the rows 1 through 6 of the triangle of the Narayana numbers: 1; 1,1; 1,3,1; 1,6,6,1; 1,10,20,10,1; 1,15,50,50,15,1.
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MAPLE
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seq(nops(`union`(seq({seq(binomial(n, k)*binomial(n, k-1)/n, k=1..n)}, n=1..m))), m=1..57);
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CROSSREFS
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Cf. A001263.
Sequence in context: A022335 A022780 A075353 this_sequence A025700 A033638 A136413
Adjacent sequences: A132275 A132276 A132277 this_sequence A132279 A132280 A132281
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KEYWORD
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nonn
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AUTHOR
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Emeric Deutsch (deutsch(AT)duke.poly.edu), Aug 26 2007
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