Google Sheet to elevate a matrix to the n power

Code.gs

/*
In a Google Sheet select Tools->Script Editor and copy&paste this code and save the file

You can use this function in a cell as:

=pow_matrix(A5:C7,3)

*/
function pow_matrix(a, n) {
  if( !a.map )
    return [];
  
  if( a.length != a[0].length )
    return "No es cuadrada";
  
  if( n == 1 ){
    return a;
  }
  
  var b = [];
  for(var i=0; i<a.length; i++){
    var row = [];
    for( var j=0; j<a[i].length; j++){
      row.push( a[i][j] );
    }    
    b.push(row);    
  }

  for(var v=1; v<n; v++){
    var c = [];
    for(var i=0; i<a.length; i++){
      var row = [];
      for( var j=0; j<a[i].length; j++){
        row.push( 0 );
      }    
      c.push(row);    
    }
    
    for(var i=0; i<a.length; i++){
      for( var j=0; j<a[i].length; j++){
        c[i][j]=0;
        for(var k=0; k<a[i].length; k++){
          c[i][j]+=a[i][k]*b[k][j]
        }
      }    
    }
    a = c;
  }
  return a;
}