OFFSET
1,3
COMMENTS
For all i >= 1, 3^{2*i} is a term arising from k = 9^i, where ^ is repeated concatenation. - Michael S. Branicky, Jan 24 2022
LINKS
Michael S. Branicky, Table of n, a(n) for n = 1..48
MATHEMATICA
Select[Table[Times@@Range[n, n+2]/(3n+3), {n, 0, 317*10^4}], PalindromeQ] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, May 06 2019 *)
PROG
(Python)
from itertools import count, islice
def ispal(n): s = str(n); return s == s[::-1]
def agen():
for k in count(0):
q, r = divmod(k*(k+2), 3)
if r == 0 and ispal(q):
yield k, q
print([q for k, q in islice(agen(), 31)]) # Michael S. Branicky, Jan 24 2022
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Patrick De Geest, May 15 1998
EXTENSIONS
a(26) and beyond from Michael S. Branicky, Jan 24 2022
STATUS
approved