A034186 Number of symmetric n X 4 crossword puzzle grids.

1, 3, 21, 47, 227, 499, 2321, 5087, 23429, 51263, 235881, 515691, 2372511, 5185609, 23856215, 52139887, 239863701, 524238555, 2411688233, 5270900439, 24248031407, 52995614649

Offset

1,2

Links

Table of n, a(n) for n=1..22.

Crossrefs

Cf. A001333, A034184-A034187.

Sequence in context: A318549 A217000 A360316 * A318211 A219069 A027499

Adjacent sequences: A034183 A034184 A034185 * A034187 A034188 A034189

Keyword

nonn

Author

Erich Friedman

Status

approved