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A028554
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Palindromes of form n(n+3).
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3
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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
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,2
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COMMENTS
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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
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LINKS
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PROG
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(Python)
while n < 10**12:
s = str(m)
if s == s[::-1]:
m += n
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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