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Search: id:A116963
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| A116963 |
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Inverse Moebius transform of tetrahedral numbers. |
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+0
4
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| 4, 14, 24, 49, 60, 118, 124, 214, 244, 356, 368, 608, 564, 814, 896, 1183, 1144, 1668, 1544, 2162, 2168, 2678, 2604, 3698, 3336, 4228, 4304, 5344, 4964, 6732, 5988, 7728, 7528, 8924, 8616, 11297, 9884, 12214, 12064, 14668
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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See also: A007437 Inverse Moebius transform of triangular numbers.
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FORMULA
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a(n) = SUM[d|n] (d+1)*(d+2)*(d+3)/6. a(n) = SUM[d|n] C(d+3,3). a(n) = SUM[d|n] A000292(d).
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EXAMPLE
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a(12) = ((1+1)*(1+2)*(1+3)/6) + ((2+1)*(2+2)*(2+3)/6) + ((3+1)*(3+2)*(3+3)/6) + ((4+1)*(4+2)*(4+3)/6) + ((6+1)*(6+2)*(6+3)/6) + ((12+1)*(12+2)*(12+3)/6) =
4 + 10 + 20 + 35 + 84 + 455 = 608.
a(13) = ((1+1)*(1+2)*(1+3)/6) + ((13+1)*(13+2)*(13+3)/6) = 4 + 560 = 564.
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CROSSREFS
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Cf. A000292, A007437.
Adjacent sequences: A116960 A116961 A116962 this_sequence A116964 A116965 A116966
Sequence in context: A011534 A043505 A017317 this_sequence A094930 A080286 A075381
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KEYWORD
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easy,nonn
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AUTHOR
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Jonathan Vos Post (jvospost2(AT)yahoo.com), Mar 31 2006
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