a(n) is the constant term in expansion of Product_{k=1..n} (x^prime(k) + 1/x^prime(k))^2.
A350881
a(n) is the constant term in expansion of Product_{k=1..n} (x^prime(k) + 1/x^prime(k))^2.
Terms
- a(0) =1a(1) =2a(2) =4a(3) =10a(4) =24a(5) =50a(6) =140a(7) =368a(8) =1152a(9) =3682a(10) =11784a(11) =39902a(12) =134612a(13) =463066a(14) =1635092a(15) =5818384a(16) =20684072a(17) =73693068a(18) =266943648a(19) =967762792a(20) =3533666568a(21) =13036452946a(22) =48102671884a(23) =178315730764a(24) =661567489568
External references
- oeis: A350881