Voozh

A370261

a(n) = sqrt(A370259(2*n)/(n+1)) for n >= 1.

1, 5, 65, 1449, 46561, 1968525, 103565057, 6531391313, 480749649601, 40482981221781, 3840053099665729, 405275779792031225, 47113209228513626017, 5982545638922153790749, 823992221632687352744961, 122360935410018418223907489, 19489013519781051891806113153

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

The sequence is conjectured to be integral.

LINKS

Paolo Xausa, Table of n, a(n) for n = 1..300

FORMULA

a(n) = sqrt( (T(2*n, 2*n+1) - 1)/((n+1)*(2*n)^3) ), where T(n, x) is the n-th Chebyshev polynomial of the first kind.

MAPLE

A370259 := n -> simplify( (ChebyshevT(n, n+1) - 1)/n^3 ):

seq(sqrt(A370259(2*n)/(n+1)), n = 1..20);