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  • just for fun: calculating primes only using unary numbers

    From yeti@yeti@tilde.institute to tilde.institute on Sun Feb 11 01:39:52 2024
    I somewhen had to do it!

    ------------------------------------------------------------------------
    $ cat unary_prime_generator.sh
    #!/bin/sh -e
    ##
    ## 20240211/yeti:
    ## using only unary numbers (lots of fngers) to calculate primes.
    ##

    dec() { echo ${#1} ; }

    a=11
    while test x$l != x111111111111111111111111111111111111111111
    do
    eval c=\$X$a
    if test -z "$c"
    then
    c=$a
    l=1$l
    echo "prime $l ($(dec $l)) is $c ($(dec $c))"
    fi
    d=$a$c
    while test -n "$(eval t=\$X$d ; echo $t)"
    do
    d=$d$c
    done
    eval X$d=\$c
    a=1$a
    done
    $ ./unary_prime_generator.sh | head -12
    prime 1 (1) is 11 (2)
    prime 11 (2) is 111 (3)
    prime 111 (3) is 11111 (5)
    prime 1111 (4) is 1111111 (7)
    prime 11111 (5) is 11111111111 (11)
    prime 111111 (6) is 1111111111111 (13)
    prime 1111111 (7) is 11111111111111111 (17)
    prime 11111111 (8) is 1111111111111111111 (19)
    prime 111111111 (9) is 11111111111111111111111 (23)
    prime 1111111111 (10) is 11111111111111111111111111111 (29)
    prime 11111111111 (11) is 1111111111111111111111111111111 (31)
    prime 111111111111 (12) is 1111111111111111111111111111111111111 (37)
    $ _
    ------------------------------------------------------------------------
    --
    I do not bite, I just want to play.
    --- Synchronet 3.19a-Linux NewsLink 1.113
  • From yeti@yeti@tilde.institute to tilde.institute on Sun Feb 11 01:48:28 2024
    I somewhen had to do it!

    ------------------------------------------------------------------------
    $ cat unary_prime_generator.sh
    #!/bin/sh -e
    ##
    ## 20240211/yeti:
    ## using only unary numbers (lots of fingers) to calculate primes.
    ##

    dec() { echo ${#1} ; }

    a=11
    while test x$l != x111111111111111111111111111111111111111111
    do
    eval c=\$X$a
    if test -z "$c"
    then
    c=$a
    l=1$l
    echo "prime $l ($(dec $l)) is $c ($(dec $c))"
    fi
    d=$a$c
    while test -n "$(eval t=\$X$d ; echo $t)"
    do
    d=$d$c
    done
    eval X$d=\$c
    a=1$a
    done
    $ ./unary_prime_generator.sh | head -12
    prime 1 (1) is 11 (2)
    prime 11 (2) is 111 (3)
    prime 111 (3) is 11111 (5)
    prime 1111 (4) is 1111111 (7)
    prime 11111 (5) is 11111111111 (11)
    prime 111111 (6) is 1111111111111 (13)
    prime 1111111 (7) is 11111111111111111 (17)
    prime 11111111 (8) is 1111111111111111111 (19)
    prime 111111111 (9) is 11111111111111111111111 (23)
    prime 1111111111 (10) is 11111111111111111111111111111 (29)
    prime 11111111111 (11) is 1111111111111111111111111111111 (31)
    prime 111111111111 (12) is 1111111111111111111111111111111111111 (37)
    $ _
    ------------------------------------------------------------------------
    --
    I do not bite, I just want to play.
    --- Synchronet 3.19a-Linux NewsLink 1.113