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A049480
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(2*n-1)*(n^2-n+6)/6.
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16
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1, 4, 10, 21, 39, 66, 104, 155, 221, 304, 406, 529, 675, 846, 1044, 1271, 1529, 1820, 2146, 2509, 2911, 3354, 3840, 4371, 4949, 5576, 6254, 6985, 7771, 8614, 9516, 10479, 11505, 12596, 13754, 14981, 16279, 17650, 19096, 20619, 22221
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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REFERENCES
| T. P. Martin, Shells of atoms, Phys. Reports, 273 (1996), 199-241, eq. (10).
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LINKS
| Harvey P. Dale, Table of n, a(n) for n = 1..1000
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FORMULA
| Contribution from Harvey P. Dale, Jan 01 2012: (Start)
G.f.: x*(x^3+1)/(x-1)^4.
a(1)=1, a(2)=4, a(3)=10, a(4)=21, a(n) = 4*a(n-1)-6*a(n-2)+ 4*a(n-3)- a(n-4). (End)
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MATHEMATICA
| Table[(2n-1)(n^2-n+6)/6, {n, 50}] (* or *) LinearRecurrence[{4, -6, 4, -1}, {1, 4, 10, 21}, 50] (* From Harvey P. Dale, Jan 01 2012 *)
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CROSSREFS
| 1/12*t*(2*n^3-3*n^2+n)+2*n-1 for t = 2, 4, 6, ... gives A049480, A005894, A063488, A001845, A063489, A005898, A063490, A057813, A063491, A005902, A063492, A005917, A063493, A063494, A063495, A063496.
Sequence in context: A008075 A009898 A008121 * A055908 A023538 A085360
Adjacent sequences: A049477 A049478 A049479 * A049481 A049482 A049483
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KEYWORD
| nonn,easy
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), Aug 01 2001
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