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A028565
Palindromes of form k*(k+7).
2
0, 8, 44, 494, 858, 49494, 445544, 819918, 4462644, 8853588, 8913198, 81099018, 441525144, 882060288, 8100990018, 44105250144, 49781418794, 85831713858, 447597795744, 810009900018, 889249942988, 4410052500144, 4450696960544, 4927434347294, 80512566521508, 81000099000018
OFFSET
1,2
FORMULA
a(n) = A028564(n) * (A028564(n) + 7). - Michael S. Branicky, Jan 26 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+7)):
yield k*(k+7)
print(list(islice(agen(), 28))) # Michael S. Branicky, Jan 26 2022
CROSSREFS
Sequence in context: A112908 A264819 A350128 * A366338 A129553 A174643
KEYWORD
nonn,base
EXTENSIONS
a(23) and beyond from Michael S. Branicky, Jan 26 2022
STATUS
approved