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!)
A268478 L(p) modulo p^2, where p = prime(n) and L is a Lucas number (A000032). 2
3, 4, 11, 29, 78, 14, 103, 324, 70, 204, 497, 519, 1477, 1420, 1881, 902, 1476, 3600, 3418, 2202, 5257, 317, 914, 5074, 4269, 9192, 5666, 6421, 7086, 4182, 12193, 3800, 1097, 11677, 299, 22651, 17271, 12063, 18371, 26297, 13784, 10137, 8405, 33583, 11230 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Lemma 7 from the Andrejic paper (p. 42): Prime p is a Wall-Sun-Sun prime iff L(p) == 1 (mod p^2). Therefore, a(n) = 1 iff A113650(n) = 0.

LINKS

Felix Fröhlich, Table of n, a(n) for n = 1..10000

V. Andrejic, On Fibonacci powers, Publikacije Elektrotehnickog fakulteta - serija: matematika, 17 (2006), 38-44.

FORMULA

a(n) = A180363(n) mod A001248(n). - Michel Marcus, Feb 09 2016

MATHEMATICA

Table[Mod[LucasL[Prime[n]], Prime[n]^2], {n, 60}] (* Vincenzo Librandi, Feb 09 2016 *)

PROG

(PARI) a000032(n) = fibonacci(n+1) + fibonacci(n-1)

a(n) = my(p=prime(n)); lift(Mod(a000032(p), p^2))

(MAGMA) [Lucas(p) mod p^2: p in PrimesUpTo(250)]; // Bruno Berselli, Feb 09 2016

CROSSREFS

Cf. A000032, A000040, A113650, A180363.

Sequence in context: A041231 A042129 A141723 * A180363 A100845 A019169

Adjacent sequences:  A268475 A268476 A268477 * A268479 A268480 A268481

KEYWORD

nonn

AUTHOR

Felix Fröhlich, Feb 05 2016

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 July 31 22:39 EDT 2021. Contains 346377 sequences. (Running on oeis4.)