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A134780 The square root of A134779. 1
1, 2, 1, 2, 1, 3, -1, 6, -7, 19, -33, 73, -146, 311, -652, 1392, -2977, 6420, -13899, 30247, -66078, 144911, -318853, 703768, -1557718, 3456813, -7689531, 17142887, -38296408, 85715645, -192191445, 431647744, -970958480, 2187288804, -4934101775, 11144794835, -25203825094 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..36.

MATHEMATICA

a[n_] := a[n] = Block[{k = a[n - 1] + 2, s = Sum[ a[i]*x^i, {i, 0, n - 1}]}, If[IntegerQ@ Last@ CoefficientList[ Series[ Sqrt[s + k*x^n], {x, 0, n}], x], k, k + 1]]; a[0] = 1; CoefficientList[ Series[ Sqrt[ Sum[ a[i]*x^i, {i, 0, 36}]], {x, 0, 36}], x]

CROSSREFS

Cf. A084202, A134779.

Sequence in context: A046205 A046206 A137753 * A247379 A154819 A104145

Adjacent sequences:  A134777 A134778 A134779 * A134781 A134782 A134783

KEYWORD

sign

AUTHOR

Paul D. Hanna & Robert G. Wilson v, Nov 11 2007

STATUS

approved

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Last modified May 21 08:53 EDT 2019. Contains 323441 sequences. (Running on oeis4.)