code: function queryPublicSeedByRoundIndex( oConn, nRoundIndex, pfnCallback )
  {
  	if ( ! oConn )
  	{
  		return pfnCallback( `call queryPublicSeedByRoundIndex with invalid oConn` );
  	}
  	if ( 'number' !== typeof nRoundIndex || nRoundIndex <= 0 )
  	{
  		return pfnCallback( `call queryPublicSeedByRoundIndex with invalid nRoundIndex` );
  	}
  
  	oConn.query
  	(
  		"SELECT seed \
  		FROM round \
  		WHERE round_index = ?",
  		[
  			nRoundIndex
  		],
  		function( arrRows )
  		{
  			if ( 0 === arrRows.length )
  			{
  				return pfnCallback( `seed not found.` );
  			}
  
  			return pfnCallback( null, arrRows[ 0 ][ 'seed' ] );
  		}
  	);
  }
docs: get public seed by round index
  
  @param	{handle}	oConn
  @param	{function}	oConn.query
  @param	{number}	nRoundIndex
  @param	{function}	pfnCallback( err, arrCoinBaseList )