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

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 59th year, we have over 358,000 sequences, and we’ve crossed 10,300 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A247525 a(n) = 5 * a(n-1) - 2 * a(n-1)^2 / a(n-2), with a(0) = 1, a(1) = 2. 1
1, 2, 2, 6, -6, -42, 378, 8694, -356454, -31011498, 5240943162, 1797643504566, -1224195226609446, -1673474874775112682, 4566912933261282509178, 24949045354406386347639414, -272468524315472145302570040294, -5952619850720119958425247670303018 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..83

FORMULA

0 = a(n)*(-5*a(n+1) + a(n+2)) + a(n+1)*(+2*a(n+1)) for all n in Z.

a(n+1) = a(n) * A140966(n) for all n in Z.

MATHEMATICA

RecurrenceTable[{a[n] == 5*a[n - 1] - 2*a[n - 1]^2/a[n - 2], a[0] == 1, a[1] == 2}, a, {n, 0, 50}] (* G. C. Greubel, Aug 05 2018 *)

PROG

(PARI) {a(n) = if( n<0, 1 / prod(k=1, -n, (5 + (-2)^-k) / 3), prod(k=0, n-1, (5 + (-2)^k) / 3))};

(Magma) I:=[1, 2]; [n le 2 select I[n] else 5*Self(n-1) - 2*Self(n-1)^2/Self(n-2): n in [1..30]]; // G. C. Greubel, Aug 05 2018

CROSSREFS

Cf. A140966.

Sequence in context: A076929 A265642 A186944 * A305295 A174789 A210865

Adjacent sequences: A247522 A247523 A247524 * A247526 A247527 A247528

KEYWORD

sign

AUTHOR

Michael Somos, Sep 18 2014

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified November 29 12:15 EST 2022. Contains 358424 sequences. (Running on oeis4.)