OFFSET
1,1
COMMENTS
Indices of Lucas numbers that are abundant numbers (A005101).
The asymptotic density of this sequence is larger than 71/700 = 0.1014... (Wall, 1982).
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..142
Charles R. Wall, Problem H-338, Advanced Problems and Solutions, The Fibonacci Quarterly, Vol. 20, No. 1 (1982), p. 94; Some Abundance, Solution to Problem H-338 by the proposer, ibid., Vol. 21, No. 2 (1983), pp. 159-160.
MATHEMATICA
Select[Range[0, 250], DivisorSigma[-1, LucasL[#]] > 2 &]
PROG
(Python) from sympy import divisor_sigma, lucas
print([k for k in range(150) if divisor_sigma(lucas(k)) > 2*lucas(k)])
# Karl-Heinz Hofmann, Feb 07 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
Amiram Eldar, Feb 05 2022
STATUS
approved