The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A199338 y-values in the solution to 15*x^2 - 14 = y^2. 2
 1, 11, 19, 89, 151, 701, 1189, 5519, 9361, 43451, 73699, 342089, 580231, 2693261, 4568149, 21203999, 35964961, 166938731, 283151539, 1314305849, 2229247351, 10347508061, 17550827269, 81465758639, 138177370801, 641378561051, 1087868139139, 5049562729769 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS When are both n+1 and 15*n+1 perfect squares? This problem gives the equation 15*x^2-14=y^2. Essentially the same as A103201. - R. J. Mathar, Nov 11 2011 LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..200 Index entries for linear recurrences with constant coefficients, signature (0, 8, 0, -1). FORMULA a(n+4) = 8*a(n+2) - a(n) with a(1)=1, a(2)=11, a(3)=19, a(4)=89. G.f.: x*(1+x)*(1+10*x+x^2)/(1-8*x^2+x^4). - Bruno Berselli, Nov 08 2011 MATHEMATICA LinearRecurrence[{0, 8, 0, -1}, {1, 11, 19, 89}, 50] PROG (MAGMA) m:=29; R:=PowerSeriesRing(Integers(), m); Coefficients(R!(x*(1+x)*(1+10*x+x^2)/(1-8*x^2+x^4))); // Bruno Berselli, Nov 08 2011 CROSSREFS Cf. A199336. Sequence in context: A229542 A039365 A103201 * A043188 A043968 A199329 Adjacent sequences:  A199335 A199336 A199337 * A199339 A199340 A199341 KEYWORD nonn,easy AUTHOR Sture Sjöstedt, Nov 08 2011 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified October 20 05:51 EDT 2020. Contains 337897 sequences. (Running on oeis4.)