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Search: id:A033579
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| A033579 |
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Four times pentagonal numbers: 2*n*(3*n-1). |
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+0
6
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| 0, 4, 20, 48, 88, 140, 204, 280, 368, 468, 580, 704, 840, 988, 1148, 1320, 1504, 1700, 1908, 2128, 2360, 2604, 2860, 3128, 3408, 3700, 4004, 4320, 4648, 4988, 5340, 5704, 6080, 6468, 6868, 7280, 7704
(list; graph; listen)
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OFFSET
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0,2
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FORMULA
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a(n) = 4n(3n-1)/2 = 6n^2 - 2n = A000326(n)*4. [From Omar E. Pol (info(AT)polprimos.com), Dec 11 2008]
a(n) = A049450(n)*2. [From Omar E. Pol (info(AT)polprimos.com), Dec 13 2008]
a(n)=12*n+a(n-1)-20 (with a(1)=0) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 12 2009]
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EXAMPLE
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For n=2, a(2)=12*2+0-20=4; n=3, a(3)=12*3+4-20=20; n=4, a(4)=12*4+20-20=48 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 12 2009]
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MATHEMATICA
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s=0; lst={s}; Do[s+=n++ +4; AppendTo[lst, s], {n, 0, 7!, 12}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Nov 16 2008]
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CROSSREFS
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Cf. A049450, A014642, A033580.
Cf. A000326. [From Omar E. Pol (info(AT)polprimos.com), Dec 11 2008]
Sequence in context: A163365 A145194 A164924 this_sequence A160799 A164014 A108099
Adjacent sequences: A033576 A033577 A033578 this_sequence A033580 A033581 A033582
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KEYWORD
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nonn,new
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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