Skabelon:WEEKDATE2Y

[expression "{{{1}}} + (((7*{{{2}}}+{{{3}}}-10+(700000006 - {{{1}}} - ((({{{1}}}-1)/4 -0.499) round 0) + ({{{1}}}>=250) * ( 5 + ((({{{1}}}-1)/100 -0.499) round 0) - (({{{1}}}-1)/400 -0.499) round 0)) mod 7-74.8- (((({{{1}}}) mod 4 = 0) and (({{{1}}}) mod 100 != 0)) or (({{{1}}}) mod 400 = 0)))/30.6 round 0)mod 12+3-0 - 6.5 ) / 12 round 0" in weekdate2m gives system message ""]