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A008501
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7-dimensional centered tetrahedral numbers.
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2
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1, 9, 45, 165, 495, 1287, 3003, 6435, 12869, 24301, 43713, 75417, 125475, 202203, 316767, 483879, 722601, 1057265, 1518517, 2144493, 2982135, 4088655, 5533155, 7398411, 9782829, 12802581, 16593929
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| If X is an n-set and Y a fixed 8-subset of X then a(n-8) is equal to the number of 8-subsets of X intersecting Y. - Milan R. Janjic (agnus(AT)blic.net), Jul 30 2007
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LINKS
| Vincenzo Librandi, Table of n, a(n) for n = 0..10000
Milan Janjic, Two Enumerative Functions
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FORMULA
| Expansion of (1-x^8 )/(1-x)^9 = (1+x)*(1+x^2)*(1+x^4) / (x-1)^8.
1260*a(n) = (2*n+1)*(n^6+3*n^5 +100*n^4 +195*n^3 +1159*n^2+1062*n+1260). - R. J. Mathar, Mar 14 2011
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PROG
| (MAGMA) [((2*n+1)*(n^6+3*n^5 +100*n^4 +195*n^3 +1159*n^2 +1062*n +1260)/1260) : n in [0..30]]; // Vincenzo Librandi, Oct 08 2011
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CROSSREFS
| Sequence in context: A095166 A126899 A162602 * A008491 A023034 A000581
Adjacent sequences: A008498 A008499 A008500 * A008502 A008503 A008504
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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