OFFSET
1,1
COMMENTS
Conjecture: every number composed of the numeral six repeated n times and ending in the numeral 8 is a term of this sequence. - Harvey P. Dale, Jun 16 2022
From Zhao Hui Du, Mar 11 2024: (Start)
Six repeated n times and ending with 8 can be written as (6/9)*(10^n-1)+2. The square of it can be written as (4/9)*(10^(2*n)-1)+(16/9)*(10^n-1)+4. Or
444444...44444...444
+ 1777...776
+ 4
----------------------
444444...46222...224. (End)
LINKS
Zhao Hui Du, Table of n, a(n) for n = 1..47
MATHEMATICA
Select[Range[700000], SubsetQ[{2, 4, 6}, IntegerDigits[#^2]]&] (* The program generates the first 12 terms of the sequence. To generate more, increase the Range constant but the program may take a long time to run. *) (* Harvey P. Dale, Jun 16 2022 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Patrick De Geest, Mar 15 2000
EXTENSIONS
More terms from C. Ronaldo (aga_new_ac(AT)hotmail.com), Jan 04 2005
Two more terms from Jon E. Schoenfield, Sep 04 2006
STATUS
approved