You are right, the trep
argument is an argument of TraMineR seqrep
function which looks for representative sequences covering at least a trep
percentage of all sequences.
If you specifically want the most frequent sequence patterns such that their cumulated percent frequencies is say 50%, then you have to compute the selection filter your self. Here is how you can do that using the biofam data.
library(TraMineR)
data(biofam)
bf.seq <- seqdef(biofam[,10:25])
## first retrieve the "Percent" column of the frequency table provided
## as the "freq" attribute of the object returned by the seqtab function.
bf.freq <- seqtab(bf.seq, tlim=nrow(bf.seq))
bf.tab <- attr(bf.freq,"freq")
bf.perct <- bf.tab[,"Percent"]
## Compute the cumulated percentages
bf.cumsum <- cumsum(bf.perct)
## Now we can use the cumulated percentage to select
## the wanted patterns
bf.freq50 <- bf.freq[bf.cumsum <= 50,]
## And to plot the frequent patterns
(nfreq <- length(bf.cumsum[bf.cumsum <= 50]))
seqfplot(bf.seq, tlim=1:nfreq)
Hope this helps.