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0, 20, 100, 280, 600, 1100, 1820, 2800, 4080, 5700, 7700, 10120, 13000, 16380, 20300, 24800, 29920, 35700, 42180, 49400, 57400, 66220, 75900, 86480, 98000, 110500, 124020, 138600, 154280, 171100, 189100, 208320, 228800, 250580, 273700
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OFFSET
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0,2
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COMMENTS
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A016755 are odd cubes and A001845 are centered octahedral numbers, so the sequence might be regarded as odd cubes without their octahedral content.
A000330 are square pyramidal numbers.
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LINKS
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Vincenzo Librandi, Table of n, a(n) for n = 0..10000
Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).
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FORMULA
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a(n) = (10/3)*n*(n + 1)*(2*n + 1).
a(n) = 20 * A000330(n).
G.f.: 20*x*(1+x)/(1-x)^4. - Klaus Brockhaus, Mar 20 2011
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MAPLE
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(10/3)*n*(n+1)*(2*n+1)
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MATHEMATICA
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10n(n+1)(2n+1)/3
LinearRecurrence[{4, -6, 4, -1}, {0, 20, 100, 280}, 40] (* Harvey P. Dale, Jul 18 2016 *)
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PROG
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(MAGMA) A016755:=func< n | (2*n+1)^3 >; A001845:=func< n | (2*n+1)*(2*n^2+2*n+3)/3 >; [ A016755(n)-A001845(n): n in [0..40] ]; // Klaus Brockhaus, Mar 20 2011
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CROSSREFS
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Cf. A016755, A001845, A000330.
Sequence in context: A128676 A039455 A294112 * A027986 A240437 A174078
Adjacent sequences: A188047 A188048 A188049 * A188051 A188052 A188053
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KEYWORD
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nonn,easy
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AUTHOR
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Damien Pras, Mar 19 2011
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STATUS
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approved
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