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0, 5, 21, 48, 86, 135, 195, 266, 348, 441, 545, 660, 786, 923, 1071, 1230, 1400, 1581, 1773, 1976, 2190, 2415, 2651, 2898, 3156, 3425, 3705, 3996, 4298, 4611, 4935, 5270, 5616, 5973, 6341, 6720, 7110
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| Number of sets with two elements which can be obtained by selecting unique elements from two sets with 2n and 3n elements respectively and n common elements. - Polina S. Dolmatova (polinasport(AT)mail.ru), Jul 11 2003
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LINKS
| Index to sequences with linear recurrences with constant coefficients, signature (3,-3,1).
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FORMULA
| G.f.: x*(5+6*x)/(1-x)^3. - Bruno Berselli, Feb 11 2011
a(n)=11*n+a(n-1)-6. - Vincenzo Librandi, Aug 04 2010
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MATHEMATICA
| s=0; lst={s}; Do[s+=n++ +5; AppendTo[lst, s], {n, 0, 7!, 11}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Nov 16 2008]
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CROSSREFS
| Cf. index to sequence with numbers of the form n*(d*n+10-d)/2 in A140090.
Sequence in context: A166010 A146846 A041825 * A201279 A146721 A099979
Adjacent sequences: A022265 A022266 A022267 * A022269 A022270 A022271
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KEYWORD
| nonn,easy
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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