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 A204040 Triangle T(n,k), read by rows, given by (0, 2, -2, 1, 0, 0, 0, 0, 0, 0, 0, ...) DELTA (1, 0, 0, 0, 0, 0, 0, 0, ...) where DELTA is the operator defined in A084938. 0
 1, 0, 1, 0, 2, 1, 0, 0, 4, 1, 0, -4, 4, 6, 1, 0, -4, -8, 12, 8, 1, 0, 4, -24, -4, 24, 10, 1, 0, 12, -8, -60, 16, 40, 12, 1, 0, 4, 56, -84, -96, 60, 60, 14, 1, 0, -20, 88, 84, -272, -100, 136, 84, 16, 1, 0, -28, -40 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,5 COMMENTS Antidiagonal sums : periodic sequence 1, 0, 1, 2, 1, 0, 1, 2, 1, 0, 1, 2, ... (see A007877 or A098178).Riordan array (1, x*(1+x)/(1-x+2*x^2)) . LINKS FORMULA T(n,k) = T(n-1,k) + T(n-1,k-1) + T(n-2, k-1) - 2*T(n-2,k). G.f.: (1-x+2*x^2)/(1-(1+y)*x + (2-y)*x^2). T(n,n) = n = A000012(n), T(n+1,n) = 2n = A005843(n), T(n+2,n) = A046092(n-1) for n>0, T(n+1,1) = A078050(n)*(-1)^n. Sum_{k, 0<=k<=n} T(n,k) = A060747(n) = A005408(n-1). EXAMPLE Triangle begins : 1 0, 1 0, 2, 1 0, 0, 4, 1 0, -4, 4, 6, 1 0, -4, -8, 12, 8, 1 0, 4, -24, -4, 24, 10, 1 0, 12, -8, -60, 16, 40, 12, 1 0, 4, 56, -84, -96, 60, 60, 14, 1 0, -20, 88, 84, -272, -100, 136, 84, 16, 1 CROSSREFS Cf. A005408. Sequence in context: A110509 A113953 A319574 * A325773 A220779 A347928 Adjacent sequences:  A204037 A204038 A204039 * A204041 A204042 A204043 KEYWORD sign,tabl AUTHOR Philippe Deléham, Jan 27 2012 STATUS approved

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Last modified May 22 00:02 EDT 2022. Contains 353931 sequences. (Running on oeis4.)