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Search: id:A153745
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| A153745 |
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Numbers n such that the number of digits d in n^2 is not prime and for each factor of d the sum of digit groupings of size d is a square. |
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+0
9
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| 1, 2, 3, 39, 60, 86, 90, 321, 347, 401, 3387, 3414, 3578, 3900, 4767, 6000, 6549, 6552, 6744, 6780, 6783, 7387, 7862, 7889, 8367, 8598, 8600, 8773, 8898, 9000, 9220, 9884, 9885, 10000, 10001, 10002, 10003, 10004, 10005, 10010, 10011, 10012, 10013, 10020
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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This sequence is a subset of A061910
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EXAMPLE
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39^2 = 1521; 1+5+2+1 = 9 = 3^2 and 15+21 = 36 = 6^2.
321^2 = 103041; 1+0+3+0+4+1 = 9 = 3^2; 10+30+41 = 81 = 9^2; and 103+041 = 144 = 12^2
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CROSSREFS
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Cf. A061910, A004159
Subsequences: A153746, A153747, A153748, A153749, A153750, A153751, A153752, A153753
Sequence in context: A041329 A060813 A039820 this_sequence A076724 A080393 A111683
Adjacent sequences: A153742 A153743 A153744 this_sequence A153746 A153747 A153748
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KEYWORD
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nonn,base
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AUTHOR
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Doug Bell (bell.doug(AT)gmail.com), Dec 31 2008, corrected Jan 19 2009
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