The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A195623 Numerators of Pythagorean approximations to 5. 4
 99, 10101, 1030199, 105070201, 10716130299, 1092940220301, 111469186340399, 11368764066500401, 1159502465596700499, 118257882726796950501, 12061144535667692250599, 1230118484755377812610601, 125460024300512869194030699 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS See A195500 for discussion and list of related sequences; see A195622 for Mathematica program. LINKS Colin Barker, Table of n, a(n) for n = 1..497 Index entries for linear recurrences with constant coefficients, signature (101,101,-1). FORMULA From Colin Barker, Jun 03 2015: (Start) a(n) = 101*a(n-1) + 101*a(n-2) - a(n-3). G.f.: x*(99+102*x-x^2)/((1+x)*(1-102*x+x^2)). (End) a(n) = (1/26)*(25*A097726(n) + (-1)^n). - G. C. Greubel, Feb 16 2023 MATHEMATICA Table[(5*LucasL[2*n+1, 10] +2*(-1)^n)/52, {n, 40}] (* G. C. Greubel, Feb 16 2023 *) PROG (PARI) Vec(-x*(x^2-102*x-99) / ((x+1)*(x^2-102*x+1)) + O(x^20)) \\ Colin Barker, Jun 03 2015 (Magma) I:=[99, 10101, 1030199]; [n le 3 select I[n] else 101*Self(n-1) +101*Self(n-2) -Self(n-3): n in [1..40]]; // G. C. Greubel, Feb 16 2023 (SageMath) A097726=BinaryRecurrenceSequence(102, -1, 1, 103) [(1/26)*(25*A097726(n) + (-1)^n) for n in range(1, 41)] # G. C. Greubel, Feb 16 2023 CROSSREFS Cf. A097726, A097727, A195500, A195622. Sequence in context: A171415 A327926 A098609 * A274743 A244842 A190921 Adjacent sequences: A195620 A195621 A195622 * A195624 A195625 A195626 KEYWORD nonn,easy,frac AUTHOR Clark Kimberling, Sep 22 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 | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified September 27 00:17 EDT 2023. Contains 365669 sequences. (Running on oeis4.)