#include <bits/stdc++.h>
#include <cmath>
#include <iomanip>
using namespace std;

using uint = unsigned int; using i64 = long long; using ui64 = unsigned long long; using i128 = __int128;
const int INF = 1e9; const i64 LLNF = 4e18;

template< class Tp > void chkmax( Tp &x, Tp y ) { x = max( x, y ); }
template< class Tp > void chkmin( Tp &x, Tp y ) { x = min( x, y ); }

using ld = double;

constexpr int B = 100; vector< ld > fact;
void prework( ) { fact = vector< ld >( B + 1 ); fact[1] = 0; for( int i = 2; i <= B; i ++ ) fact[i] = fact[i - 1] + log( i ); }
ld factorial( int n ) { if( n <= B ) return fact[n]; else return n * log( n ) - n; }
ld binom( int n, int m ) { if( m < 0 || m > n ) return -INFINITY; else return factorial( n ) - factorial( m ) - factorial( n - m ); }

// Phi( n, m ) = log( sum( binom( n, k ) * 2 ^ k: 0 <= k <= m ) )
ld Phi( int n, int m ) { int k = min( m, 2 * n / 3 ); return binom( n, k ) + log( 2 ) * k; }

void solve( ) {
	int n, m; cin >> n >> m;
	cout << fixed << setprecision( 10 ) << log( 3 * m + 1 ) + n * log( 3 ) - Phi( n, m ) << "\n";
}

int main( ) {
	ios::sync_with_stdio( 0 ), cin.tie( 0 ), cout.tie( 0 );
	prework( ); int T; cin >> T; while( T -- ) solve( ); return 0;
}