This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A128380 #9 Jan 09 2025 02:49:32 %S A128380 1,0,-48,-24,1104,1128,-15892,-25368,156240,360640,-1057908,-3600696, %T A128380 4417678,26438568,-3155508,-144207816,-112109568,564538680,1002957320, %U A128380 -1344487080,-5096138658,-111333800,17182425012,17552839368,-34668142443,-86942440944,4993723500,236551774320 %N A128380 A097806^24 * A000594. %C A128380 Conjecture: Given the infinite set of sequences generated from the pairwise operation on A000594 (A097806^k * A000594), k = 24, (A128380) is the only sequence in the set with a zero. The sequence generated from k=23 = (1, -1, -47, 23, 1081, 47, -15939, ...). Analogous conjecture with the partial sum operator: (Cf. A128378, A128379); in which zeros are conjectured to occur only with k=23 and k=24. A128380 mod 24 = 1, 0, 0, 0, 0, 0, -4, 0, 0, 16, ... %F A128380 Pairwise operation performed 24 times on A000594 %t A128380 Nest[Prepend[Most[#] + Rest[#], First[#]] &, RamanujanTau[Range[30]], 24] (* _Amiram Eldar_, Jan 08 2025 *) %Y A128380 Cf. A000594, A097806, A128378, A128379. %K A128380 sign %O A128380 1,3 %A A128380 _Gary W. Adamson_, Feb 28 2007 %E A128380 More terms from _Amiram Eldar_, Jan 08 2025