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Search: id:A099089
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| 1, 0, 2, 0, 1, 4, 0, 0, 4, 8, 0, 0, 1, 12, 16, 0, 0, 0, 6, 32, 32, 0, 0, 0, 1, 24, 80, 64, 0, 0, 0, 0, 8, 80, 192, 128, 0, 0, 0, 0, 1, 40, 240, 448, 256, 0, 0, 0, 0, 0, 10, 160, 672, 1024, 512, 0, 0, 0, 0, 0, 1, 60, 560, 1792, 2304, 1024, 0, 0, 0, 0, 0, 0, 12, 280, 1792, 4608, 5120, 2048
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OFFSET
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0,3
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COMMENT
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Row sums are A000129. Diagonal sums are A008346. The Riordan array (1,s+tx) defines T(n,k)=binomial(k,n-k)s^k(t/s)^(n-k). The row sums satisfy a(n)=s*a(n-1)+t*a(n-2) and the diagonal sums satisfy a(n)=s*a(n-2)+t*a(n-3).
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FORMULA
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Number triangle T(n, k)=binomial(k, n-k)2^k(1/2)^(n-k) Columns have g.f. (2x+x^2)^k.
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EXAMPLE
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Rows begin {1}, {0,2}, {0,1,4}, {0,0,4,8}, {0,0,0,1,12,6},...
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CROSSREFS
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Cf. A053118, A008312.
Sequence in context: A072737 A061290 A099096 this_sequence A121298 A121462 A131487
Adjacent sequences: A099086 A099087 A099088 this_sequence A099090 A099091 A099092
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KEYWORD
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easy,nonn,tabl
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AUTHOR
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Paul Barry (pbarry(AT)wit.ie), Sep 25 2004
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