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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A167779 Subsequence of A167708 whose indices are congruent to 4 mod 5, i.e., a(n) = A167708(5n+4). 7
105, 35634, 12115455, 4119219066, 1400522366985, 476173485555834, 161897584566616575, 55044702579164079666, 18715036979331220469865, 6363057528270035795674434, 2163420844574832839308837695, 735556724097914895329209141866, 250087122772446489579091799396745 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..250

Index entries for linear recurrences with constant coefficients, signature (340,-1).

FORMULA

a(n+2) = 340*a(n+1) - a(n).

a(n+1) = 170*a(n) + 39*sqrt(19*a(n)^2 - 1539).

G.f.: (105 - 66*z)/(1 - 340*z + z^2).

a(n) = ((105 + 24*sqrt(19))/2)*(170 + 39*sqrt(19))^(n) + ((105 - 24*sqrt(19) )/2)*(170 - 39*sqrt(19))^(n).

EXAMPLE

a(0) = A167708(4) = 105, a(1) = A167708(9) = 35634, ...

MAPLE

u(0):=105:u(1):=35634:for n from 0 to 20 do u(n+2):=340*u(n+1)-u(n):od:seq(u(n), n=0..20); taylor(((105+35634*z-105*z*340)/(1-340*z+z^2)), z=0, 20); for n from 0 to 20 do u(n):=simplify((24*sqrt(19)+105)/2*(170+39*sqrt(19))^(n)+(-24*sqrt(19)+105)/2*(170-39*sqrt(19))^(n)):od:seq(u(n), n=0..20);

MATHEMATICA

LinearRecurrence[{340, -1}, {105, 35634}, 50] (* G. C. Greubel, Jun 23 2016 *)

PROG

(MAGMA) I:=[105, 35634]; [n le 2 select I[n] else 340*Self(n-1)-Self(n-2): n in [1..20]]; // Vincenzo Librandi, Jun 25 2016

CROSSREFS

Cf. A167708, A167709, A167774, A167775, A167778, A167780.

Sequence in context: A111647 A295463 A145621 * A275461 A054862 A028917

Adjacent sequences:  A167776 A167777 A167778 * A167780 A167781 A167782

KEYWORD

easy,nonn

AUTHOR

Richard Choulet, Nov 11 2009

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 6 10:57 EDT 2020. Contains 334837 sequences. (Running on oeis4.)