A219187 Sum of distinct prime divisors of Lucas(n).

2, 0, 3, 2, 7, 11, 5, 29, 47, 21, 44, 199, 32, 521, 284, 44, 2207, 3571, 112, 9349, 2168, 242, 353, 600, 1152, 263, 90484, 5800, 14510, 19548, 2567, 3010349, 5568, 10102, 63513, 1022, 103713, 54018521, 29134604, 1461, 4689, 370248451, 1796, 151190, 2118, 785

Offset

0,1

Links

Amiram Eldar, Table of n, a(n) for n = 0..1000

Formula

a(n) = A008472(A000032(n)). - Amiram Eldar, Sep 03 2019

Example

a(6) = 5 because Lucas(6) = 21 and the sum of the prime divisors {3, 7} equals 10.

Maple

with (numtheory):with(combinat, fibonacci):
sopf:= proc(n) local e, j; e := ifactors(fibonacci(n+1)+fibonacci(n-1))[2]:
add (e[j][1], j=1..nops(e)) end:
seq (sopf(n), n=0..100);

Mathematica

Array[If[#==1, 0, Plus@@First/@FactorInteger[LucasL[ # ]]]&, 50, 0]

Crossrefs

Cf. A000032, A008472, A080648, A219177.

Sequence in context: A007492 A135351 A079451 * A049799 A087985 A200927

Adjacent sequences: A219184 A219185 A219186 * A219188 A219189 A219190

Keyword

nonn

Author

Michel Lagneau, Nov 14 2012

Extensions

a(0) prepended by Amiram Eldar, Sep 03 2019

Status

approved