Initial data commit

Task/Yellowstone-sequence/Forth/yellowstone-sequence.fth

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+: array create cells allot ;
+: th cells + ;                         \ some helper words
+
+30 constant #yellow                    \ number of yellowstones
+
+#yellow array y                        \ create array
+                                       ( n1 n2 -- n3)
+: gcd dup if tuck mod recurse exit then drop ;
+: init 3 0 do i 1+ y i th ! loop ;     ( --)
+: show cr #yellow 0 do y i th ? loop ; ( --)
+: gcd-y[] - cells y + @ over gcd ;     ( k i n -- k gcd )
+: loop1 begin 1+ over 2 gcd-y[] 1 = >r over 1 gcd-y[] 1 > r> or 0= until ;
+: loop2 over true swap 0 ?do over y i th @ = if 0= leave then loop ;
+: yellow #yellow 3 do i 3 begin loop1 loop2 until y rot th ! loop ;
+: main init yellow show ;
+
+main