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 A349038 G.f. A(x) satisfies: A(x) = 1 / (1 + x - 2 * x * A(-2*x)). 2
 1, 1, -3, -31, 453, 15641, -973443, -126707471, 32192101173, 16547934365321, -16912274385623763, -34670312866958030751, 141940412456349939507813, 1163060052394732038435530361, -19053251054424307861590927924003, -624375047526738670923288994646642991 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS FORMULA a(0) = 1; a(n) = -a(n-1) - Sum_{k=0..n-1} (-2)^(k+1) * a(k) * a(n-k-1). MATHEMATICA nmax = 15; A[_] = 0; Do[A[x_] = 1/(1 + x - 2 x A[-2 x]) + O[x]^(nmax + 1) // Normal, nmax + 1]; CoefficientList[A[x], x] a[0] = 1; a[n_] := a[n] = -a[n - 1] - Sum[(-2)^(k + 1) a[k] a[n - k - 1], {k, 0, n - 1}]; Table[a[n], {n, 0, 15}] CROSSREFS Cf. A001003, A015097, A348901. Sequence in context: A087591 A061053 A047798 * A126346 A142999 A212917 Adjacent sequences:  A349035 A349036 A349037 * A349039 A349040 A349041 KEYWORD sign AUTHOR Ilya Gutkovskiy, Nov 06 2021 STATUS approved

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Last modified August 11 20:13 EDT 2022. Contains 356067 sequences. (Running on oeis4.)