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A139563
Fibonacci numbers whose digit sum is a Lucas number.
2
1, 2, 3, 13, 21, 34, 610, 196418, 1134903170, 20365011074, 15635695580168194910579363790217849593217, 1049252690665646467530632231274619718410203796555123147644873726135009824265250
OFFSET
1,2
COMMENTS
Depending on whether the Lucas numbers are defined by A000032 or by A000204, one obtains this sequence here or A117766. - R. J. Mathar, Nov 03 2008
The next term (a(13)) has 108 digits. - Harvey P. Dale, Jul 01 2022
EXAMPLE
196418 is a Fibonacci number whose digit sum 29 is a Lucas number.
MATHEMATICA
luQ[n_] := n==2 || Block[{i=1}, While[LucasL[i] < n, i++]; LucasL[i] == n]; Select[
Fibonacci[ Range[2, 400]], luQ[ Plus @@ IntegerDigits[#]] &] (* Giovanni Resta, Mar 15 2020 *)
Module[{nn=500, ln=LucasL[Range[0, 20]]}, Select[Fibonacci[Range[nn]], MemberQ[ ln, Total[ IntegerDigits[ #]]]&]]//Union (* Harvey P. Dale, Jul 01 2022 *)
CROSSREFS
KEYWORD
nonn,base,less
AUTHOR
Parthasarathy Nambi, Jun 11 2008
EXTENSIONS
1 added in front by R. J. Mathar, Nov 03 2008
More terms from Jinyuan Wang, Mar 15 2020
STATUS
approved