Similar to 虚数単位

1 − 1 + 2 − 6 + 24 − 120 + ⋯

1 − 2 + 3 − 4 + ⋯

1 − 2 + 4 − 8 + ⋯

1/2 + 1/4 + 1/8 + 1/16 + ⋯

1/2 − 1/4 + 1/8 − 1/16 + ⋯

1/4 + 1/16 + 1/64 + 1/256 + ⋯

Plane (mathematics)

Two's complement

Bipartite graph

Three-dimensional space

Three-valued logic

Four-dimensional space

Four fours

Five lemma

Five-dimensional space

Six-dimensional space

Figure-eight knot (mathematics)

Nine lemma

Hundredth

One-form (differential geometry)

Partition of unity

Two-form

Sums of three cubes

Ages of Three Children puzzle

4-manifold

68–95–99.7 rule