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A100156
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Structured truncated tetrahedral numbers.
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3
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1, 12, 44, 108, 215, 376, 602, 904, 1293, 1780, 2376, 3092, 3939, 4928, 6070, 7376, 8857, 10524, 12388, 14460, 16751, 19272, 22034, 25048, 28325, 31876, 35712, 39844, 44283, 49040, 54126, 59552
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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LINKS
| Vincenzo Librandi, Table of n, a(n) for n = 1..5000
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FORMULA
| a(n) = (1/6)*(11*n^3-3*n^2-2*n).
a(0)=1, a(1)=12, a(2)=44, a(3)=108, a(n) = 4*a(n-1)-6*a(n-2)+4*a(n-3)- a(n-4). G.f.: x*(2*x*(x+4)+1)/(x-1)^4. - Harvey P. Dale, Sep 28 2011
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MATHEMATICA
| Table[(11n^3-3n^2-2n)/6, {n, 40}] (* or *) LinearRecurrence[{4, -6, 4, -1}, {1, 12, 44, 108}, 40] (* From Harvey P. Dale, Sep 28 2011 *)
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PROG
| (MAGMA) [(1/6)*(11*n^3-3*n^2-2*n): n in [1..40]]; // Vincenzo Librandi, Jul 19 2011
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CROSSREFS
| Cf. A100155, A100157 for adjacent structured Archimedean solids; A100145 for more on structured polyhedral numbers. Similar to truncated tetrahedral numbers A005906.
Sequence in context: A009519 A106808 A007899 * A194284 A009785 A135710
Adjacent sequences: A100153 A100154 A100155 * A100157 A100158 A100159
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KEYWORD
| easy,nonn
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AUTHOR
| James A. Record (james.record(AT)gmail.com). Nov 07, 2004.
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