OFFSET
0,3
COMMENTS
Table 1 of Andrica 2021 paper (p. 24) refers to A002203 as "Pell-Lucas" numbers.
LINKS
Michael De Vlieger, Table of n, a(n) for n = 0..10000
Dorin Andrica, Ovidiu Bagdasar, and George Cătălin Tųrcąs, On some new results for the generalised Lucas sequences, An. Şt. Univ. Ovidius Constanţa (Romania, 2021) Vol. 29, No. 1, 17-36. See Section 5.2, pp. 32-33, Table 3.
EXAMPLE
The Pell-Lucas numbers A002203 are 2, 2, 6, 14, 34, 82, ...
a(0)=a(1)=0, since there are no Pell-Lucas numbers less than or equal to 0 and 1, respectively.
a(2)=a(3)=a(4)=a(5)=2, since the first 2 Pell-Lucas numbers, 2 and 2, are less than or equal to 2, 3, 4, and 5, respectively.
MATHEMATICA
Block[{a = 2, b = -1, nn = 64, u, v = {}}, u = {2, a}; Do[AppendTo[u, Total[{-b, a} u[[-2 ;; -1]]]]; AppendTo[v, Count[u, _?(# <= i &)]], {i, nn}]; {Boole[First[u] <= 0]}~Join~v] (* Michael De Vlieger, Jun 16 2021 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Ovidiu Bagdasar, Jun 16 2021
STATUS
approved