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 A206306 Riordan array (1, x/(1-3*x+2*x^2)). 1
 1, 0, 1, 0, 3, 1, 0, 7, 6, 1, 0, 15, 23, 9, 1, 0, 31, 72, 48, 12, 1, 0, 63, 201, 198, 82, 15, 1, 0, 127, 522, 699, 420, 125, 18, 1, 0, 255, 1291, 2223, 1795, 765, 177, 21, 1, 0, 511, 3084, 6562, 6768, 3840, 1260, 238, 24, 1 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,5 COMMENTS Triangle T(n,k), read by rows, given by (0, 3, -2/3, 2/3, 0, 0, 0, 0, 0, 0, 0, ...) DELTA (1, 0, 0, 0, 0, 0, 0, 0, ...) where DELTA is the operator defined in A084938. Diagonals sums are even indexed Fibonacci numbers. LINKS FORMULA Sum_{k, 0<=k<=n} T(n,k)*x^k = A000007(n), A204089(n), A204091(n) for x = 0, 1, 2 respectively. G.f.: (1-3*x+2*x^)/(1-(3+y)*x+2*x^2). T(n,n) = 1, T(n+1,n) = 3n = A008585(n), T(n+2,n) = A062725(n). T(n,k)=3*T(n-1,k)+T(n-1,k-1)-T(n-2,k), T(0,0)=T(1,1)=T(2,2)=1, T(1,0)=T(2,0)=0, T(2,1)=3, T(n,k)=0 if k<0 or if k>n. - Philippe Deléham, Nov 17 2013 EXAMPLE Triangle begins : 1 0, 1 0, 3, 1 0, 7, 6, 1 0, 15, 23, 9, 1 0, 31, 72, 48, 12, 1 0, 63, 201, 198, 82, 15, 1 0, 127, 522, 699, 420, 125, 18, 1 0, 255, 1291, 2223, 1795, 765, 177, 21, 1 0, 511, 3084, 6562, 6768, 3840, 1260, 238, 24, 1 0, 1023, 7181, 18324, 23276, 16758, 7266, 1932, 308, 27, 1 CROSSREFS Cf. Columns : A000007, A000225 (Mersenne numbers), A045618, A055582, Cf. A110441 Sequence in context: A176108 A110504 A111246 * A178124 A143395 A090536 Adjacent sequences:  A206303 A206304 A206305 * A206307 A206308 A206309 KEYWORD easy,nonn,tabl AUTHOR Philippe Deléham, Feb 06 2012 STATUS approved

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