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A028562
Palindromes of form k*(k+6).
3
0, 7, 55, 616, 19591, 76167, 515515, 749947, 7474747, 72999927, 236799997632, 769437734967, 1900289820091, 2998954598992, 5170703070715, 5934592954395, 29175111157192, 51175166157115, 57154688645175, 211106050601112, 570608929806075, 574823545328475
OFFSET
1,2
FORMULA
a(n) = A028561(n) * (A028561(n) + 6). - Michael S. Branicky, Jan 25 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+6)):
yield k*(k+6)
print(list(islice(agen(), 19))) # Michael S. Branicky, Jan 25 2022
CROSSREFS
Sequence in context: A159313 A318580 A054910 * A209668 A340028 A365030
KEYWORD
nonn,base
EXTENSIONS
a(20) and beyond from Michael S. Branicky, Jan 25 2022
STATUS
approved