Online PHP editor | refs for jZZ5S

<?php function isPerfect($n) { return $n[0]*$n[1]*$n[2]*$n[3]+1==pow(pow($n[0],2)+3*$n[0]+1,2); } var_dump(isPerfect([1,2,3,4])); var_dump(isPerfect(['1','2','3','4'])); var_dump(isPerfect([3,9,5,6])); var_dump(isPerfect([1,2,3,4,5])); var_dump(isPerfect([a,b,c,d])); var_dump(isPerfect([1,b,3,4])); var_dump(isPerfect([1001,1002,1003,1004]));