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A147651
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First trisection of A028560.
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1
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0, 27, 72, 135, 216, 315, 432, 567, 720, 891, 1080, 1287, 1512, 1755, 2016, 2295, 2592, 2907, 3240, 3591, 3960, 4347, 4752, 5175, 5616, 6075, 6552, 7047, 7560, 8091, 8640, 9207, 9792, 10395, 11016
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refs;
listen;
history;
text;
internal format)
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OFFSET
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0,2
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COMMENTS
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Nonnegative k such that k/9 + 1 is a square. - Bruno Berselli, Apr 10 2018
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LINKS
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FORMULA
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a(n) = 9*n*(n+2).
a(n) = a(n-1) + 9*A144396(n) for n>0.
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MATHEMATICA
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PROG
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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