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Search: id:A128908
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| A128908 |
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Riordan array (1,x/(1-x)^2). |
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+0
2
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| 1, 0, 1, 0, 2, 1, 0, 3, 4, 1, 0, 4, 10, 6, 1, 0, 5, 20, 21, 8, 1, 0, 6, 35, 56, 36, 10, 1, 0, 7, 56, 126, 120, 55, 12, 1, 0, 8, 84, 252, 330, 220, 78, 14, 1, 0, 9, 120, 462, 792, 715, 364, 105, 16, 1, 0, 10, 165, 792, 1716, 2002, 1365, 560, 136, 18, 1
(list; table; graph; listen)
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OFFSET
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0,5
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COMMENT
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Triangle T(n,k), 0<=k<=n, read by rows given by [0,2,-1/2,1/2,0,0,0,0,0,...] DELTA [1,0,0,0,0,0,0,0,...] where DELTA is the operator defined in A084938 .
Row sums give A088305 . - Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Nov 21 2007
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FORMULA
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T(n,0)=0^n, T(n,k)=binomial(n+k-1,2k-1) for k>=1 .
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EXAMPLE
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Triangle begins:
1;
0, 1;
0, 2, 1;
0, 3, 4, 1;
0, 4, 10, 6, 1;
0, 5, 20, 21, 8, 1;
0, 6, 35, 56, 36, 10, 1;
0, 7, 56, 126, 120, 55, 12, 1;
0, 8, 84, 252, 330, 220, 78, 14, 1;
0, 9, 120, 462, 792, 715, 364, 105, 16, 1;
0, 10, 165, 792, 1716, 2002, 1365, 560, 136, 18, 1 ;...
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CROSSREFS
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Cf. A007318, A078812, A034008.
Adjacent sequences: A128905 A128906 A128907 this_sequence A128909 A128910 A128911
Sequence in context: A049242 A108887 A095884 this_sequence A101603 A124030 A106378
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KEYWORD
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nonn,tabl
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AUTHOR
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Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Apr 22 2007
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