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A349037 G.f. A(x) satisfies: A(x) = 1 / (1 - x - x^2 * A(-4*x)). 2
1, 1, 2, -1, 29, 116, 7701, -103563, 31343898, 1759289595, 2057705197793, -457070362176172, 2156748187140412361, 1921405067209313680505, 36188075164863127910696914, -128870933294125665748520896793, 9713904752944734908048841134573557 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..16.

FORMULA

a(0) = 1; a(n) = a(n-1) + Sum_{k=0..n-2} (-4)^k * a(k) * a(n-k-2).

MATHEMATICA

nmax = 16; A[_] = 0; Do[A[x_] = 1/(1 - x - x^2 A[-4 x]) + O[x]^(nmax + 1) // Normal, nmax + 1]; CoefficientList[A[x], x]

a[0] = 1; a[n_] := a[n] = a[n - 1] + Sum[(-4)^k a[k] a[n - k - 2], {k, 0, n - 2}]; Table[a[n], {n, 0, 16}]

CROSSREFS

Cf. A001006, A015099, A348880, A349035, A349036.

Sequence in context: A246909 A249269 A245621 * A351710 A321442 A005693

Adjacent sequences:  A349034 A349035 A349036 * A349038 A349039 A349040

KEYWORD

sign

AUTHOR

Ilya Gutkovskiy, Nov 06 2021

STATUS

approved

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Last modified May 21 05:37 EDT 2022. Contains 353889 sequences. (Running on oeis4.)