A198943 y-values in the solution to 10*x^2-9 = y^2.

1, 9, 41, 79, 351, 1559, 3001, 13329, 59201, 113959, 506151, 2248079, 4327441, 19220409, 85367801, 164328799, 729869391, 3241728359, 6240166921, 27715816449, 123100309841, 236962014199, 1052471155671, 4674570045599, 8998316372641, 39966188099049, 177510561422921

Offset

1,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..250

Index entries for linear recurrences with constant coefficients, signature (0,0,38,0,0,-1).

Formula

a(n+6) = 38*a(n+3)-a(n) with a(1)=1, a(2)=9, a(3)=41, a(4)=79, a(5)=351.

G.f.: x*(1+x)*(1+8*x+33*x^2+8*x^3+x^4)/(1-38*x^3+x^6). - Bruno Berselli, Nov 04 2011

Mathematica

LinearRecurrence[{0, 0, 38, 0, 0, -1}, {1, 9, 41, 79, 351, 1559}, 27]  (* Bruno Berselli, Nov 11 2011 *)

Crossrefs

Cf. A052454.

Sequence in context: A159754 A045804 A322055 * A000451 A000437 A095809

Adjacent sequences: A198940 A198941 A198942 * A198944 A198945 A198946

Keyword

nonn,easy

Author

Sture Sjöstedt, Oct 31 2011

Extensions

More terms from Bruno Berselli, Nov 04 2011

Status

approved