inputlist = [2,12,35,51,57,58]
combined = combinations(inputlist, 3)

series = Series(list(g) for k, g in groupby(combined, key=itemgetter(0)))

0    [(2, 12, 35), (2, 12, 51), (2, 12, 57), (2, 12...
1    [(12, 35, 51), (12, 35, 57), (12, 35, 58), (12...
2           [(35, 51, 57), (35, 51, 58), (35, 57, 58)]
3                                       [(51, 57, 58)]

ID      DATE        _1  _2  _3  _4  _5  _6

405     2002-10-19  2   12  32  38  47  48
615     2004-11-17  2   12  16  24  26  54
732     2006-01-28  2   12  26  31  43  46
1361    2012-02-11  2   12  19  22  36  58
1472    2013-03-02  2   12  33  57  58  60
1523    2013-08-24  2   12  40  46  52  53
1711    2015-06-10  2   12  19  29  50  59
2142    2019-04-17  2   12  35  51  57  58