%I A161706
%S A161706 1,2,4,5,10,20,21,27,201,626,1486,3035,5608,9632,15637,24267,
%T A161706 36291,52614,74288,102523,138698,184372,241295,311419,396909,
%U A161706 500154,623778,770651,943900,1146920,1383385,1657259,1972807
%V A161706 1,2,4,5,10,20,21,-27,-201,-626,-1486,-3035,-5608,-9632,-15637,-24267,
%W A161706 -36291,-52614,-74288,-102523,-138698,-184372,-241295,-311419,-396909,
%X A161706 -500154,-623778,-770651,-943900,-1146920,-1383385,-1657259,-1972807
%N A161706 (-11*n^5 + 145*n^4 - 635*n^3 + 1115*n^2 - 494*n + 120)/120.
%C A161706 {a(k): 0 <= k < 6} = divisors of 20:
%C A161706 a(n) = A027750(A006218(19) + k + 1), 0 <= k < A000005(20).
%H A161706 R. Zumkeller, <a href="a161700.txt">Enumerations of Divisors</a>
%F A161706 a(n) = C(n,0) + C(n,1) + C(n,2) - 2*C(n,3) + 7*C(n,4) - 11*C(n,5).
%e A161706 Differences of divisors of 20 to compute the coefficients of their interpolating 
               polynomial, see formula:
%e A161706 1 ... 2 ... 4 ... 5 ... 10 ... 20
%e A161706 .. 1 ... 2 ... 1 ... 5 ... 10
%e A161706 ..... 1 .. -1 ... 4 ... 5
%e A161706 ....... -2 ... 5 ... 1
%e A161706 ........... 7 .. -4
%e A161706 ............ -11.
%Y A161706 A005408, A000124, A016813, A086514, A000125, A058331, A002522, A161701, 
               A161702, A161703, A000127, A161704, A161707, A161708, A161710, A080856, 
               A161711, A161712, A161713, A161715, A006261.
%Y A161706 A005018, A161700, A161856. [From Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), 
               Jun 21 2009]
%Y A161706 Sequence in context: A000675 A005018 A118551 this_sequence A128401 A018467 
               A035524
%Y A161706 Adjacent sequences: A161703 A161704 A161705 this_sequence A161707 A161708 
               A161709
%K A161706 sign
%O A161706 0,2
%A A161706 Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Jun 17 2009