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Sum of the first n Lucas numbers whose indices are prime.
1

%I #19 Sep 08 2022 08:46:18

%S 3,7,18,47,246,767,4338,13687,77766,1227617,4237966,58256487,

%T 428504938,1397827967,8041666846,127260518217,2266556004016,

%U 7867304297817,108368654581246,797215157169645,2600638713977566,34961761386236715,256768195924215394

%N Sum of the first n Lucas numbers whose indices are prime.

%C Partial sums of A180363.

%H Vincenzo Librandi, <a href="/A279482/b279482.txt">Table of n, a(n) for n = 1..500</a>

%F From _Jon E. Schoenfield_, Dec 18 2016: (Start)

%F a(n) = Sum_{i=1..n} A180363(i).

%F a(n) = Sum_{i=1..n} A000032(A000040(i)). (End)

%t Accumulate[LucasL[Prime[Range[25]]]]

%o (Magma) [&+[Lucas(NthPrime(i)): i in [1..n]]: n in [1..30]];

%Y Cf. A000032, A000040, A111136, A180363.

%K nonn

%O 1,1

%A _Vincenzo Librandi_, Dec 13 2016