OFFSET
1,1
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
FORMULA
a(n) = n*3^floor(log_3(n)+1) + n. - Ilya Gutkovskiy, Jan 26 2018
EXAMPLE
50_10 = 1212_3. - Jon E. Schoenfield, Feb 11 2021
MATHEMATICA
b3iQ[n_]:=Module[{idn3=IntegerDigits[n, 3], len}, len=Length[idn3]; EvenQ[ len] && Take[idn3, len/2]==Take[idn3, -len/2 ]]; Select[Range[5000], b3iQ] (* Harvey P. Dale, Feb 08 2015 *)
a[n_] := n + n*3^Floor[Log[3, n] + 1]; Array[a, 50] (* Amiram Eldar, Apr 06 2021 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
David W. Wilson, Melia Aldridge (ma38(AT)spruce.evansville.edu)
STATUS
approved