1=2·2·3 2=2·2·2·5 3=2·2·2·2·2·2 4=2·2·3·3 5=2·2·3·5 6=5·13 7=2·2·5 8=2·3·5 9=2·2·2·7 10=3·7 11=2·3·3 12=2·2·2·2 13=2·3·3·5·7 14=7·11·13 15=5·5·5·5 16=2·2·2·2·5·5 17=2·2·2·2·5·5·5 18=2·2·2·2·5·7
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