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
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
KEYWORD
nonn
AUTHOR
Felix Fröhlich, Feb 05 2016
STATUS
approved