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Diffstat (limited to 'Master/texmf-dist/doc/latex/expose-expl3-dunkerque-2019/codes/knuth-def.tex')
-rw-r--r-- | Master/texmf-dist/doc/latex/expose-expl3-dunkerque-2019/codes/knuth-def.tex | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/Master/texmf-dist/doc/latex/expose-expl3-dunkerque-2019/codes/knuth-def.tex b/Master/texmf-dist/doc/latex/expose-expl3-dunkerque-2019/codes/knuth-def.tex new file mode 100644 index 00000000000..34c771501e1 --- /dev/null +++ b/Master/texmf-dist/doc/latex/expose-expl3-dunkerque-2019/codes/knuth-def.tex @@ -0,0 +1,20 @@ +\newif\ifprime \newif\ifunknown +\newcount\n \newcount\p +\newcount\d \newcount\a + +\def \primes#1{2,~3\n=#1 \advance \n by-2 \p=5 + \loop \ifnum \n>0 \printifprime \advance \p by2 \repeat} + +\def \printp{, \ifnum \n=1 and~\fi + \number \p \advance \n by -1 } + +\def \printifprime{\testprimality \ifprime\printp\fi} + +\def \testprimality{{\d=3 \global \primetrue + \loop \trialdivision \ifunknown \advance \d by2 \repeat}} + +\def \trialdivision{\a=\p \divide \a by\d + \ifnum \a>\d \unknowntrue \else \unknownfalse \fi + \multiply \a by\d \ifnum \a=\p \global \primefalse \unknownfalse \fi} + +\endinput
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