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A028554
Palindromes of form n(n+3).
3
0, 4, 88, 868, 4554, 8008, 45154, 89698, 452254, 4526254, 8996998, 830333038, 862626268, 899969998, 4058008504, 45032023054, 45229592254, 89999699998, 405485584504, 4503764673054, 8187727277818, 8999996999998, 89178266287198, 455467838764554, 833066101660338
OFFSET
1,2
COMMENTS
Also: Palindromes that are the sum of consecutive initial even composites. Sequence 4 + 6 + 8 + 10 + 12 + 14 + ... + z = n. For values of z see A058851. (Comment added by author 12/2000).
9*10^(2n)-3*10^n-2 for n >= 0 are terms. For n > 1, the first (and last digit) of a(n) is either 4 or 8. - Chai Wah Wu, Feb 20 2021
LINKS
PROG
(Python)
n, m, A028554_list = 4, 0, []
while n < 10**12:
s = str(m)
if s == s[::-1]:
A028554_list.append(m)
m += n
n += 2 # Chai Wah Wu, Feb 20 2021
CROSSREFS
Sequence in context: A059577 A239007 A254652 * A303153 A154137 A154136
KEYWORD
nonn,base
EXTENSIONS
More terms from Chai Wah Wu, Feb 20 2021
STATUS
approved