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A048653
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Numbers n such that n^2 can be partitioned into 2 or more numbers that are also squares.
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2
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7, 12, 13, 19, 21, 35, 37, 38, 41, 44, 57, 65, 70, 107, 108, 112, 119, 120, 121, 125, 129, 130, 190, 191, 204, 205, 209, 210, 212, 223, 253, 285, 305, 306, 315, 342, 343, 345, 350, 369, 370, 379, 380, 408, 410, 413, 440, 441, 475, 487, 501, 538, 570, 642, 650
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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LINKS
| Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
M. L. Perez et al., eds., Smarandache Notions Journal
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EXAMPLE
| 12 is present because 12^2=144 can be partitioned into three squares 1, 4 and 4.
108^2 = 11664 = 1_16_64, 120^2 = 14400 = 1_4_400, so 108 and 120 are in the sequence.
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PROG
| (Haskell)
a048653 n = a048653_list !! (n-1)
a048653_list = filter (f . show . (^ 2)) [1..] where
f zs = g (init $ tail $ inits zs) (tail $ init $ tails zs)
g (xs:xss) (ys:yss)
| h xs = h ys || f ys || g xss yss
| otherwise = g xss yss
where h ds = head ds /= '0' && a010052 (read ds) == 1
g _ _ = False
-- Reinhard Zumkeller, Oct 11 2011
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CROSSREFS
| Cf. A048646, A048375.
Cf. A010052, A000290; subsequence of A128783.
Sequence in context: A070420 A083681 A178660 * A205807 A075696 A061120
Adjacent sequences: A048650 A048651 A048652 * A048654 A048655 A048656
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KEYWORD
| base,nice,nonn
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AUTHOR
| Felice Russo (frusso(AT)micron.com)
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EXTENSIONS
| Corrected and extended by Naohiro Nomoto (6284968128(AT)geocities.co.jp), Sep 01 2001
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