Specialization at T = -284/39 of a rank-17 fibration of X1152 not posted before: y^2 = x^3 + A4 x + A6, where
A4 = -9879263860426790634432T^8 + 86542933653687887807616T^7 - 135085452380206943680656T^6 - 670355493830703722869488T^5 - 1051946747940271972123080T^4 - 3373640011473668508665088T^3 - 849884467368517694646336T^2 + 3646401529809912988876056T - 1342215706985392840165467,
A6 = 376157002259901169222608370611456T^12 - 5012568105195271642968657466363392T^11 + 20939308987938975132973897671040896T^10 + 13327362718284003523861442478906240T^9 - 278883358041208378819482351125270640T^8 + 367979789534049131266298576914822080T^7 + 2889329182749276846125866347500564400T^6 + 1554211227618089538131391252658550640T^5 - 3013942383637349393404424222146644840T^4 + 631952356094086111413853506833246400T^3 + 2160468957381686900407596405190211280T^2 - 2226612923028643159215506958258590280T + 628996598302785742517854074617969910.
It is a 2-neighbour of another fibration built here (itself a 2-neighbour of the fibration in curve#3900): its Mordell-Weil lattice (rank 17, no reducible fibres) is a root-free Kneser 2-neighbour of that fibration's, realised by the pencil |O + P - F| for a section P of height 12. Constructed and searched by Claude (Anthropic): a Mestre-Nagao sieve over the fibration, then a 2-covering point search seeded with its generic sections.
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