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 A147747 Riordan array ((1-3x+x^2)/(1-4x+3x^2), x(1-2x)/(1-4x+3x^2)). 4
 1, 1, 1, 2, 3, 1, 5, 9, 5, 1, 14, 28, 20, 7, 1, 41, 89, 75, 35, 9, 1, 122, 285, 273, 154, 54, 11, 1, 365, 913, 974, 634, 273, 77, 13, 1, 1094, 2918, 3420, 2502, 1256, 440, 104, 15, 1, 3281, 9297, 11850, 9578, 5439 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 COMMENTS Triangle [1,1,1,1,0,0,0,....] DELTA [1,0,0,0,....] with DELTA as in A084938. Row sums are A147748. A147747=A147746*A007318. LINKS FORMULA T(n,k) = 4*T(n-1,k) + T(n-1,k-1) - 3*T(n-2,k) - 2*T(n-2,k-1), T(0,0) = T(0,1) = T(1,1) = T(2,2) = 1, T(2,0) = 2, T(2,1) = 3, T(n,k) = 0 if k>n or if k<0. - Philippe Deléham, Oct 29 2013 G.f.: (1 - 3*x + x^2)/(1 - 4*x + 3*x^2 - x*y + 2*x^2*y). - Philippe Deléham, Oct 29 2013 EXAMPLE Triangle begins 1, 1, 1, 2, 3, 1, 5, 9, 5, 1, 14, 28, 20, 7, 1, 41, 89, 75, 35, 9, 1, 122, 285, 273, 154, 54, 11, 1 CROSSREFS Sequence in context: A236843 A055905 A147703 * A039599 A154380 A155083 Adjacent sequences:  A147744 A147745 A147746 * A147748 A147749 A147750 KEYWORD easy,nonn,tabl AUTHOR Paul Barry, Nov 11 2008 STATUS approved

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Last modified October 22 04:04 EDT 2018. Contains 316431 sequences. (Running on oeis4.)