A262361 - OEIS

%I #28 Apr 01 2021 14:54:08

%S 4,1,7,29,1149851,387739824812222466915538827541705412334749

%N a(n) = L(L(L(n))), where L(n) are Lucas numbers A000032.

%C a(6) = 3393011755..4322744978 has 1208 decimal digits and a(7) = 4437405101..8830136999 has 240305 decimal digits.

%H Alois P. Heinz, <a href="/A262361/b262361.txt">Table of n, a(n) for n = 0..5</a>

%p L:= n-> (<<0|1>, <1|1>>^n. <<2, 1>>)[1$2]:

%p a:= n-> L(L(L(n))):

%p seq(a(n), n=0..5);

%t A262361 = Nest[LucasL, #, 3] &; Array[A262361, 6, 0] (* _JungHwan Min_, Nov 09 2016 *)

%o (Python)

%o from sympy import lucas as L

%o def a(n):  return L(L(L(n)))

%o print([a(n) for n in range(6)]) # _Michael S. Branicky_, Apr 01 2021

%Y Cf. A000032, A005371, A058051.

%K nonn

%O 0,1

%A _Alois P. Heinz_, Nov 09 2016