A355724 Row 4 of table A355721.

1, 2, 22, 314, 5326, 102722, 2197558, 51355514, 1297759918, 35208930050, 1020115715542, 31432396066106, 1026506419425550, 35428218801977666, 1288967076156307702, 49323199246104202874, 1980947315202528449518, 83342865788161594337282, 3666525676611059535630742

Offset

0,2

Links

Table of n, a(n) for n=0..18.

A. N. Stokes, Continued fraction solutions of the Riccati equation, Bull. Austral. Math. Soc. Vol. 25 (1982), 207-214.

Formula

O.g.f: A(x) = ( Sum_{k >= 0} d(k+4)/d(4)*x^k )/( Sum_{k >= 0} d(k+3)/d(3)*x^k ), where d(n) = Product_{k = 1..n} (2*k-1) = A001147(n).

A(x) = 1/(1 + 7*x - 9*x/(1 + 9*x - 11*x/(1 + 11*x - 13*x/(1 + 13*x - ... )))).

The o.g.f. satisfies the Riccati differential equation 2*x^2*A'(x) + 7*x*A(x)^2 - (1 + 5*x)*A(x) + 1 = 0 with A(0) = 1.

Applying Stokes 1982 gives A(x) = 1/(1 - 2*x/(1 - 9*x/(1 - 4*x/(1 - 11*x/(1 - 6*x/(1 - 13*x/(1 - ... - 2*n*x/(1 - (2*n+7)*x )))))))), a continued fraction of Stieltjes-type.

Maple

n := 4: seq(coeff(series( hypergeom([n+1/2, 1], [], 2*x)/hypergeom([n-1/2, 1], [], 2*x ), x, 21), x, k), k = 0..20);

Crossrefs

Cf. A001147, A355721 (table), A112934 (row 0), A000698 (row 1), A355722 (row 2), A355723 (row 3), A355725 (row 5).

Sequence in context: A349107 A368447 A299824 * A266888 A155674 A279619

Adjacent sequences: A355721 A355722 A355723 * A355725 A355726 A355727

Keyword

nonn,easy

Author

Peter Bala, Jul 15 2022

Status

approved