We prove lim Bₙ^ (8) /sₙ = (7/32) ζ (3) for the level-8 Apéry-like sequence sₙ = Σ C (n, k) ²C (2k, n) ² and its rational companion Bₙ^ (8), and deduce the Ramanujan Machine conjecture Z1: PCF ( (2n+1) (3n²+3n+1), −n⁶) = 8/ (7ζ (3) ). The value was identified by Almkvist–van Straten–Zudilin (2008) and stated by Golyshev (arXiv: 0908. 1458) ; this is the first complete proof. Method: eta-product parametrization, Eichler integral, Mellin–Barnes period polynomial, singularity transfer. The companion result Z2 was proved in arXiv: 2604. 06239. https: //arxiv. org/abs/2604. 14219
Alex Shvets (Sat,) studied this question.