a 4 + b 4 + c 4 + 4 ( a 3 b + a b 3 + a 3 c + b 3 c + a c 3 + b c 3 ) + 6 ( a 2 b 2 + a 2 c 2 + b 2 c 2 ) + 12 ( a 2 b c + a b 2 c + a b c 2 ) {\displaystyle {}a^{4}+b^{4}+c^{4}+4(a^{3}b+ab^{3}+a^{3}c+b^{3}c+ac^{3}+bc^{3})+6(a^{2}b^{2}+a^{2}c^{2}+b^{2}c^{2})+12(a^{2}bc+ab^{2}c+abc^{2})}
