OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
Index entries for linear recurrences with constant coefficients, signature (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 571538, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1).
FORMULA
G.f.: -(x^26 -2*x^25 +7*x^24 -9*x^23 +16*x^22 -25*x^21 +41*x^20 -353*x^19 +394*x^18 -747*x^17 +1141*x^16 -1888*x^15 +6805*x^14 -15498*x^13 -6805*x^12 -1888*x^11 -1141*x^10 -747*x^9 -394*x^8 -353*x^7 -41*x^6 -25*x^5 -16*x^4 -9*x^3 -7*x^2 -2*x -1)/(x^28 -571538*x^14 +1). - Vincenzo Librandi, Dec 22 2013
a(n) = 571538*a(n-14) - a(n-28) for n>27. - Vincenzo Librandi, Dec 22 2013
MATHEMATICA
Denominator[Convergents[Sqrt[340], 30]] (* Harvey P. Dale, Jun 01 2012 *)
CoefficientList[Series[-(x^26 - 2 x^25 + 7 x^24 - 9 x^23 + 16 x^22 - 25 x^21 + 41 x^20 - 353 x^19 + 394 x^18 - 747 x^17 + 1141 x^16 - 1888 x^15 + 6805 x^14 - 15498 x^13 - 6805 x^12 - 1888 x^11 - 1141 x^10 - 747 x^9 - 394 x^8 - 353 x^7 - 41 x^6 - 25 x^5 - 16 x^4 - 9 x^3 - 7 x^2 - 2 x - 1)/(x^28 - 571538 x^14 + 1), {x, 0, 30}], x] (* Vincenzo Librandi, Dec 22 2013 *)
PROG
(Magma) I:=[1, 2, 7, 9, 16, 25, 41, 353, 394, 747, 1141, 1888, 6805, 15498, 564733, 1144964, 3999625, 5144589, 9144214, 14288803, 23433017, 201752939, 225185956, 426938895, 652124851, 1079063746, 3889316089, 8857695924]; [n le 28 select I[n] else 571538*Self(n-14)-Self(n-28): n in [1..40]]; // Vincenzo Librandi, Dec 22 2013
CROSSREFS
KEYWORD
nonn,frac,easy
AUTHOR
EXTENSIONS
More terms from Vincenzo Librandi, Dec 22 2013
STATUS
approved