A079451 Highest prime dividing the n-th Lucas number (A000032); 0 when no such prime exists.

2, 0, 3, 2, 7, 11, 3, 29, 47, 19, 41, 199, 23, 521, 281, 31, 2207, 3571, 107, 9349, 2161, 211, 307, 461, 1103, 151, 90481, 5779, 14503, 19489, 2521, 3010349, 4481, 9901, 63443, 911, 103681, 54018521, 29134601, 859, 3041, 370248451, 1427, 144481, 967, 541

Offset

0,1

Links

Amiram Eldar, Table of n, a(n) for n = 0..1000 (using Blair Kelly's data)

J. Brillhart, P. L. Montgomery and R. D. Silverman, Tables of Fibonacci and Lucas factorizations, Math. Comp. 50 (1988), 251-260, S1-S15. Math. Rev. 89h:11002.

Blair Kelly, Factorizations of first 1000 Lucas numbers.

Formula

a(n) = A006530(A000032(n)). - Felix Fröhlich, Dec 26 2016

Maple

A079451 := proc(n)
    if n = 1 then
        0;
    else
        A006530(A000032(n)) ;
    end if;
end proc:
seq(A079451(n), n=0..30) ; # R. J. Mathar, Oct 26 2013

Mathematica

Join[{2, 0}, f[n_]:=(FactorInteger@LucasL@n)[[-1, 1]]; Array[f, 60, 2]] (* Vincenzo Librandi, Dec 26 2016 *)

Prog

(PARI) a(n) = my(f = factor(fibonacci(n+1)+fibonacci(n-1))); if (om = #f~, f[om, 1], 0); \\ Michel Marcus, Oct 26 2013
(Magma) [2, 0] cat [Maximum(PrimeDivisors(Lucas(n))): n in [2..60]]; // Vincenzo Librandi, Dec 26 2016

Crossrefs

Cf. A000032, A006530.

Sequence in context: A348959 A007492 A135351 * A219187 A049799 A087985

Adjacent sequences: A079448 A079449 A079450 * A079452 A079453 A079454

Keyword

nonn

Author

Lekraj Beedassy, Jan 13 2003

Extensions

More terms from Michel Marcus, Oct 26 2013

Status

approved