Multiple of 2.
Abbreviations: i.e.: id est (that is); k: knit; rep: repeat; p: purl; st.: stitch;
Row 1: *Put right needle between 1st & 2nd st. from behind (i.e. needle point facing you) & k 2nd st., k 1st st. in normal way* rep from * to* until end
Row 2: p1, *p 2nd st., p 1st st.*, rep from * to* until last st., p1
These two rows form the pattern. Repeat as required.