GAP 4.8.9 installation with standard packages -- copy to your CoCalc project to get it
#SIXFORMAT GapDocGAP
HELPBOOKINFOSIXTMP := rec(
encoding := "UTF-8",
bookname := "ThreeKPlusOne",
entries :=
[ [ "Title page", ".", [ 0, 0, 0 ], 1, 1, "title page", "X7D2C85EC87DD46E5" ],
[ "Copyright", ".-1", [ 0, 0, 1 ], 17, 2, "copyright", "X81488B807F2A1CF1" ]
, [ "Table of Contents", ".-2", [ 0, 0, 2 ], 26, 3, "table of contents",
"X8537FEB07AF2BEC8" ],
[
"\033[1X\033[33X\033[0;-2YThe \033[22X3k+1\033[122X\033[101X\027\033[1X\\
027 Problem\033[133X\033[101X", "1", [ 1, 0, 0 ], 1, 4, "the 3k+1 problem",
"X8769FB038733F6F4" ],
[ "\033[1X\033[33X\033[0;-2YTheory\033[133X\033[101X", "1.1", [ 1, 1, 0 ],
4, 4, "theory", "X8729B87B848E3F89" ],
[ "\033[1X\033[33X\033[0;-2YProgram\033[133X\033[101X", "1.2", [ 1, 2, 0 ],
20, 4, "program", "X7A4605C07A94C9F6" ],
[ "Bibliography", "bib", [ "Bib", 0, 0 ], 1, 5, "bibliography",
"X7A6F98FD85F02BFE" ],
[ "References", "bib", [ "Bib", 0, 0 ], 1, 5, "references",
"X7A6F98FD85F02BFE" ],
[ "Index", "ind", [ "Ind", 0, 0 ], 1, 6, "index", "X83A0356F839C696F" ],
[ "\033[2XThreeKPlusOneSequence\033[102X", "1.2-1", [ 1, 2, 1 ], 25, 4,
"threekplusonesequence", "X7B1A31B8870EA092" ] ]
);