| m0=: A=: # %~ +/ | Arithmetic mean | 
| m1=: G=: # %: */ | Geometric mean | 
| m2=: H=: A&.(%"_) | Harmonic mean | 
| m3=: C=: [: {. (A,G)^:_ | Common mean; arithmetic-geometric mean (de Kerf [2]) | 
| m4=: A&(^&3) | Mean of cubes | 
| a5=: (^&) (A&) | Generalized x-mean | 
| m6=: m4 -: 3 a5 | Tautology | 
| a7=: (^&) (A&.) | L-x norm | 
| m8=: (^&3)@(3 a7) -: (3 a5) | Tautology | 
| v9=: MA=: A\ | x-period moving average of y | 
| m10=: +/\  -: +/\.&.|. | Tautology: invariance under reverse | 
| m11=: +/\. -: +/\ &.|. | Tautology: invariance under reverse | 
| m12=: +/\^:(i.`($&1)) | Figurate numbers | 
| m13=: 1: #. ] | Sum; +/"1 | 
| m14=: +/&.(*:"_)@:+."0 | Magnitude | | 
| m15=: - |.!.0 | .+/\^:_1 | 
| d16=: psum=: ([:+/ [ ^~ i.@])"0 | Sum of powers of integers; 2 sum 7 | 
| m17=: 0&psum -: [ | Tautology: +/(i.n)^0 | 
| m18=: 1&psum -: 2&! | Tautology: +/(i.n)^1 | 
| m19=: 2&psum -: 0 1r6 _1r2 1r3&p. | Tautology: +/(i.n)^2 | 
| m20=: [ (psum %. ^/~@]) i.@(2&+) | Polynomial coeff. of +/(i.n)^k |