Andy Huchala Look And Say Sequence Factorizations (A005150) n a(n) [factors of a(n)] 1 1 [] 2 11 [11] 3 21 [3, 7] 4 1211 [7, 173] 5 111221 [11, 10111] 6 312211 [312211] 7 13112221 [13112221] 8 1113213211 [11, 19, 1831, 2909] 9 31131211131221 [5581, 5578070441] 10 13211311123113112211 [26966089, 489923144699] 11 11131221133112132113212221 [7, 19, 1093, 76572179303098543109] 12 3113112221232112111312211312113211 [20328937, 627557606587, 244020609982169] 13 1321132132111213122112311311222113111221131221 [29, 971563, 46889682313579293049990557739475858123] 14 11131221131211131231121113112221121321132132211331222113112211 [3, 31, 2531, 221587, 213414262009265690085197238570402233414850657035591] 15 311311222113111231131112132112311321322112111312211312111322212311322113212221 [3, 17, 233, 641, 128393, 985271337705217021, 323082514382425741194809828536919444925509282219] 16 132113213221133112132113311211131221121321131211132221123113112221131112311332111213211322211312113211 [3, 383, 22129, 778787563, 372186744299, 992248732068413855071496071, 18066081981418737446465764523127580786149677833] 17 11131221131211132221232112111312212321123113112221121113122113111231133221121321132132211331121321231231121113122113322113111221131221 [1637, 65899, 28011499, 2166461230384885249, 628203575567817008731, 4563149888276588170607, 593147762527424889392459746051218924337177065713118594101] 18 31131122211311123113321112131221123113112211121312211213211321322112311311222113311213212322211211131221131211132221232112111312111213111213211231131122212322211331222113112211 [103, 3680685112691464277, 60861889361267144957, 132745171868601579352790626558363782348161270226787627, 10164001552688004460863377684266235393836322584237833033727531614068750384696054879]