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A274349
Products of two distinct Lucas numbers (2,3,4,7,11,18,...).
6
6, 8, 12, 14, 21, 22, 28, 33, 36, 44, 54, 58, 72, 77, 87, 94, 116, 126, 141, 152, 188, 198, 203, 228, 246, 304, 319, 329, 369, 398, 492, 517, 522, 532, 597, 644, 796, 836, 846, 861, 966, 1042, 1288, 1353, 1363, 1368, 1393, 1563, 1686, 2084, 2189, 2204, 2214
OFFSET
1,1
LINKS
EXAMPLE
6 = 2*3, 44 = 4*11.
MAPLE
N:= 10000: # for terms <= N
L:= gfun:-rectoproc({f(n)=f(n-1)+f(n-2), f(0)=2, f(1)=1}, f(n), remember):
S:= {}:
for i from 2 do
u:= L(i);
if u > N then break fi;
for j from 0 to i-1 do
if j = 1 then next fi;
v:= u*L(j);
if v > N then break fi;
S:= S union {v};
od od:
sort(convert(S, list)); # Robert Israel, Jan 01 2021
MATHEMATICA
z = 100; f[n_] := LucasL[n]; f[1] = 2 ;
Take[Sort[Flatten[Table[f[u] f[v], {u, 1, z}, {v, 1, u - 1}]]], z]
Take[Times@@@Subsets[Join[{2}, LucasL[Range[2, 20]]], {2}]//Union, 60] (* Harvey P. Dale, Aug 13 2019 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Jun 18 2016
STATUS
approved