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 A274719 Expansion of Product_{k >= 1} (1-q^(2*k)). 0
 1, 0, -1, 0, -1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0 COMMENTS Convolution of A000009 and A010815. LINKS FORMULA Equals convolution inverse of A035363. a(2n) = A010815(n). Conjecture: |a(n)| = A089806(n). EXAMPLE G.f. = 1 - x^2 - x^4 + x^10 + x^14 - x^24 - x^30 + x^44 + x^52 - x^70 - ... - Altug Alkan, Mar 24 2018 MATHEMATICA nmax = 100; CoefficientList[ Series[Product[(1 - x^(2*k)), {k, 1, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Jul 05 2016 *) PROG (PARI) lista(nn) = {q='q+O('q^nn); Vec(eta(q^2))} \\ Altug Alkan, Mar 21 2018 CROSSREFS Cf. A000009, A010815, A035363, A089806. Sequence in context: A014141 A014093 A089806 * A014069 A154388 A285136 Adjacent sequences:  A274716 A274717 A274718 * A274720 A274721 A274722 KEYWORD sign AUTHOR George Beck, Jul 03 2016 EXTENSIONS Simpler definition from N. J. A. Sloane, Mar 24 2018 STATUS approved

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Last modified May 29 01:41 EDT 2022. Contains 354122 sequences. (Running on oeis4.)