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A028556
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Palindromes of form k*(k+4).
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2
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0, 5, 77, 252, 525, 1221, 2112, 21312, 56165, 73437, 276672, 1265621, 2114112, 2509052, 29311392, 69555596, 71588517, 122434221, 126000621, 540888045, 5401221045, 21183638112, 69069096096, 71149694117, 79158385197, 2752360632572, 7320655560237, 12278611687221
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OFFSET
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1,2
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LINKS
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FORMULA
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PROG
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(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+4)):
yield k*(k+4)
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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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