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A028571
Palindromes of form k*(k+9).
2
0, 22, 252, 2332, 20002, 26062, 29392, 63736, 68886, 2701072, 2783872, 2884882, 29122192, 253080352, 289050982, 25661316652, 237776677732, 2393677763932, 215331808133512, 218759969957812, 225588939885522, 235212787212532, 636759171957636, 682911868119286
OFFSET
1,2
FORMULA
a(n) = A028570(n) * (A028570(n) + 9). - Michael S. Branicky, Jan 26 2022
MATHEMATICA
Select[Table[k(k+9), {k, 0, 262*10^5}], PalindromeQ] (* Harvey P. Dale, Feb 13 2022 *)
PROG
(Python)
from itertools import count, islice
def ispal(n): s = str(n); return s == s[::-1]
def agen():
for k in count(0):
if ispal(k*(k+9)):
yield k*(k+9)
print(list(islice(agen(), 18))) # Michael S. Branicky, Jan 26 2022
CROSSREFS
Sequence in context: A161521 A161900 A162364 * A162679 A325742 A010974
KEYWORD
nonn,base
EXTENSIONS
a(22) and beyond from Michael S. Branicky, Jan 26 2022
STATUS
approved