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A218033 G.f. A(x) satisfies A(x) = 1 + x * A(x) / A(x^2). 1
1, 1, 1, 0, -1, -2, -2, 0, 3, 6, 6, 2, -6, -14, -16, -8, 11, 32, 42, 26, -18, -74, -108, -82, 18, 162, 268, 238, 16, -344, -656, -664, -189, 694, 1570, 1792, 826, -1294, -3668, -4698, -2866, 2110, 8364, 12034, 8960, -2432, -18508, -30134, -26254, -910, 39492, 73862, 73560, 19120 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,6

LINKS

Vincenzo Librandi and Alois P. Heinz, Table of n, a(n) for n = 0..1000 (terms up to n=200 from Vincenzo Librandi)

MATHEMATICA

m = 60; A[_] = 1;

Do[A[x_] = 1 + x A[x]/A[x^2] + O[x]^m // Normal, {m}];

CoefficientList[A[x], x] (* Jean-Fran├žois Alcover, Oct 04 2019 *)

PROG

(PARI)

N=66;  R=O('x^N);  x='x+R;

F = 1 + x;

for (k=1, N+1, F = 1 + x * F / subst(F, 'x, 'x^2) + R; );

Vec(F)

CROSSREFS

Sequence in context: A216973 A061314 A193383 * A326500 A255903 A118262

Adjacent sequences:  A218030 A218031 A218032 * A218034 A218035 A218036

KEYWORD

sign

AUTHOR

Joerg Arndt, Oct 19 2012

STATUS

approved

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Last modified October 23 02:09 EDT 2019. Contains 328335 sequences. (Running on oeis4.)