Best Known (20, s)-Sequences in Base 7
(20, 27)-Sequence over F7 — Constructive and digital
Digital (20, 27)-sequence over F7, using
(20, 53)-Sequence over F7 — Digital
Digital (20, 53)-sequence over F7, using
- t-expansion [i] based on digital (19, 53)-sequence over F7, using
- Niederreiter–Xing sequence construction II/III [i] based on function field F/F7 with g(F) = 19 and N(F) ≥ 54, using
(20, 138)-Sequence in Base 7 — Upper bound on s
There is no (20, 139)-sequence in base 7, because
- net from sequence [i] would yield (20, m, 140)-net in base 7 for arbitrarily large m, but
- m-reduction [i] would yield (20, 277, 140)-net in base 7, but
- extracting embedded OOA [i] would yield OOA(7277, 140, S7, 2, 257), but
- the (dual) Plotkin bound for OOAs shows that M ≥ 60 583333 217025 632376 642604 420619 134235 784911 500367 919816 861378 984868 836145 835314 342631 038967 488518 752345 301455 492138 386110 468381 706218 346895 180334 602780 948018 896953 700242 297751 922134 903126 648843 532419 724463 548591 136214 559711 378810 081143 / 43 > 7277 [i]
- extracting embedded OOA [i] would yield OOA(7277, 140, S7, 2, 257), but
- m-reduction [i] would yield (20, 277, 140)-net in base 7, but