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Search: id:A161706
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| A161706 |
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(-11*n^5 + 145*n^4 - 635*n^3 + 1115*n^2 - 494*n + 120)/120. |
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+0
23
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| 1, 2, 4, 5, 10, 20, 21, -27, -201, -626, -1486, -3035, -5608, -9632, -15637, -24267, -36291, -52614, -74288, -102523, -138698, -184372, -241295, -311419, -396909, -500154, -623778, -770651, -943900, -1146920, -1383385, -1657259, -1972807
(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 < 6} = divisors of 20:
a(n) = A027750(A006218(19) + k + 1), 0 <= k < A000005(20).
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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) + C(n,1) + C(n,2) - 2*C(n,3) + 7*C(n,4) - 11*C(n,5).
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EXAMPLE
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Differences of divisors of 20 to compute the coefficients of their interpolating polynomial, see formula:
1 ... 2 ... 4 ... 5 ... 10 ... 20
.. 1 ... 2 ... 1 ... 5 ... 10
..... 1 .. -1 ... 4 ... 5
....... -2 ... 5 ... 1
........... 7 .. -4
............ -11.
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CROSSREFS
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A005408, A000124, A016813, A086514, A000125, A058331, A002522, A161701, A161702, A161703, A000127, A161704, A161707, A161708, A161710, A080856, A161711, A161712, A161713, A161715, A006261.
A005018, A161700, A161856. [From Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Jun 21 2009]
Sequence in context: A000675 A005018 A118551 this_sequence A128401 A018467 A035524
Adjacent sequences: A161703 A161704 A161705 this_sequence A161707 A161708 A161709
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KEYWORD
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sign
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AUTHOR
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Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Jun 17 2009
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