Denominators of first difference of squares of harmonic numbers A001008/A002805.

Terms

a(0) =1a(1) =4a(2) =9a(3) =48a(4) =150a(5) =90a(6) =490a(7) =2240a(8) =11340a(9) =2520a(10) =152460a(11) =83160a(12) =2342340a(13) =2522520a(14) =540540a(15) =11531520a(16) =104144040a(17) =110270160a(18) =737176440a(19) =775975200a(20) =162954792a(21) =56904848a(22) =1368302936a(23) =2141691552a(24) =111546435000a(25) =116008292400