This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A219187 #17 Sep 03 2019 14:41:00 %S A219187 2,0,3,2,7,11,5,29,47,21,44,199,32,521,284,44,2207,3571,112,9349,2168, %T A219187 242,353,600,1152,263,90484,5800,14510,19548,2567,3010349,5568,10102, %U A219187 63513,1022,103713,54018521,29134604,1461,4689,370248451,1796,151190,2118,785 %N A219187 Sum of distinct prime divisors of Lucas(n). %H A219187 Amiram Eldar, <a href="/A219187/b219187.txt">Table of n, a(n) for n = 0..1000</a> %F A219187 a(n) = A008472(A000032(n)). - _Amiram Eldar_, Sep 03 2019 %e A219187 a(6) = 5 because Lucas(6) = 21 and the sum of the prime divisors {3, 7} equals 10. %p A219187 with (numtheory):with(combinat,fibonacci): %p A219187 sopf:= proc(n) local e, j; e := ifactors(fibonacci(n+1)+fibonacci(n-1))[2]: %p A219187 add (e[j][1], j=1..nops(e)) end: %p A219187 seq (sopf(n), n=0..100); %t A219187 Array[If[#==1, 0, Plus@@First/@FactorInteger[LucasL[ # ]]]&, 50, 0] %Y A219187 Cf. A000032, A008472, A080648, A219177. %K A219187 nonn %O A219187 0,1 %A A219187 _Michel Lagneau_, Nov 14 2012 %E A219187 a(0) prepended by _Amiram Eldar_, Sep 03 2019