ceprn ecprn cpern pcern epcrn pecrn cerpn ecrpn crepn rcepn ercpn recpn cpren pcren crpen rcpen prcen rpcen eprcn percn erpcn repcn precn rpecn cepnr ecpnr cpenr pcenr epcnr pecnr cenpr ecnpr cnepr ncepr encpr necpr cpner pcner cnper ncper pncer npcer epncr pencr enpcr nepcr pnecr npecr cernp ecrnp crenp rcenp ercnp recnp cenrp ecnrp cnerp ncerp encrp necrp crnep rcnep cnrep ncrep rncep nrcep erncp rencp enrcp nercp rnecp nrecp cprne pcrne crpne rcpne prcne rpcne cpnre pcnre cnpre ncpre pncre npcre crnpe rcnpe cnrpe ncrpe rncpe nrcpe prnce rpnce pnrce nprce rnpce nrpce eprnc pernc erpnc repnc prenc rpenc epnrc penrc enprc neprc pnerc nperc ernpc renpc enrpc nerpc rnepc nrepc prnec rpnec pnrec nprec rnpec nrpec
Note: these 'words' (valid or invalid) are all the permutations of the word ceprn. These words are obtained by scrambling the letters in ceprn.