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完全平方公式或者是直角三角形内角的度数比是4：5：9
(a±b)²=a²±2ab+b²
(a+b)²=a²+2ab+b²
4 5 9 4^2+5^2+40=9^2=81
22 ? 366 484+?^2+44*?=133956

..1....1.....1......1.......1.......1........1........1........1.........1
..2....3.....4......5.......6.......7........8........9.......10........11
..2....6....12.....20......30......42.......56.......72.......90.......110
..5...22....57....122.....223.....366......563......820.....1143......1544
..8...68...274....766....1722....3376.....6004.....9928....15514.....23178
.20..264..1464...5238...14430...33468....68722...128844...225126....371858
.38..988..7974..37044..125322..344456...817362..1738516..3397474...6205668
.88.3954.45050.270832.1123612.3656654.10024344.24184890.52854218.106749960

填77
1×4+1=5
2×5+1-2=9
3×9+1-2-4=22
4×22+1-2-4-6=77
5×77+1-2-4-6-8=366