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Search: id:A161712
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| A161712 |
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(4*n^3 - 6*n^2 + 8*n + 3)/3. |
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+0
22
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| 1, 3, 9, 27, 65, 131, 233, 379, 577, 835, 1161, 1563, 2049, 2627, 3305, 4091, 4993, 6019, 7177, 8475, 9921, 11523, 13289, 15227, 17345, 19651, 22153, 24859, 27777, 30915, 34281, 37883, 41729, 45827, 50185, 54811, 59713, 64899, 70377, 76155
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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{a(k): 0 <= k < 4} = divisors of 27:
a(n) = A027750(A006218(26) + k + 1), 0 <= k < A000005(27).
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LINKS
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R. Zumkeller, Enumerations of Divisors
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FORMULA
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a(n) = C(n,0) + 2*C(n,1) + 4*C(n,2) + 8*C(n,3).
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EXAMPLE
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Differences of divisors of 27 to compute the coefficients of their interpolating polynomial, see formula:
1 ... 3 ... 9 ... 27
.. 2 ... 6 .. 18
..... 4 .. 12
........ 8.
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CROSSREFS
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A005408, A000124, A016813, A086514, A000125, A058331, A002522, A161701, A161702, A161703, A000127, A161704, A161706, A161707, A161708, A161710, A080856, A161711, A161713, A161715, A006261.
Sequence in context: A093546 A015955 A097803 this_sequence A137368 A036215 A103828
Adjacent sequences: A161709 A161710 A161711 this_sequence A161713 A161714 A161715
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KEYWORD
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nonn
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AUTHOR
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Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Jun 17 2009
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