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A047668
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Row 4 of array in A047666.
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2
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4, 17, 52, 129, 276, 529, 932, 1537, 2404, 3601, 5204, 7297, 9972, 13329, 17476, 22529, 28612, 35857, 44404, 54401, 66004, 79377, 94692, 112129, 131876, 154129, 179092, 206977, 238004, 272401, 310404, 352257, 398212, 448529
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| In this sequence if we do a forward difference, then the 3rd forward difference when considered as a sequence will be an arithmetic progression with common difference 8 [From Gopalakrishnan (gopala498(AT)yahoo.co.in), Jun 05 2010]
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FORMULA
| 1/3 * (n^4 + 8n^2 + 3).
G.f.: x*(4-3*x+7*x^2-x^3+x^4)/(1-x)^5 [From Maksym Voznyy (voznyy(AT)mail.ru), Jul 27 2009]
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CROSSREFS
| Sequence in context: A173704 A184445 A131339 * A092091 A046995 A001585
Adjacent sequences: A047665 A047666 A047667 * A047669 A047670 A047671
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
| G.f. proposed by Maksym Voznyy checked and corrected by R. J. Mathar, Sep 16 2009.
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