A076573 a(0)=1 if n>0 a(n)=(-1)^(n+1)/(2n+1) * Sum_{k=0..n} 4^(5k)*B(2k)*C(2n+1,2k) where B(k) denotes the k-th Bernoulli number.
1, 171, 34611, 25391031, 36412266951, 84746764368291, 289947183663000891, 1368522076163485223151, 8518903397471846192668431, 67614595884596632809835843611, 666443065911076418265517497701571
Offset: 0