Search: id:A161707 Results 1-1 of 1 results found. %I A161707 %S A161707 1,3,7,21,53,111,203,337,521,763,1071,1453,1917,2471,3123,3881,4753, %T A161707 5747,6871,8133,9541,11103,12827,14721,16793,19051,21503,24157,27021, %U A161707 30103,33411,36953,40737,44771,49063,53621,58453,63567,68971,74673 %N A161707 (4*n^3 - 9*n^2 + 11*n + 3)/3. %C A161707 {a(k): 0 <= k < 4} = divisors of 21: %C A161707 a(n) = A027750(A006218(20) + k + 1), 0 <= k < A000005(21). %H A161707 R. Zumkeller, Enumerations of Divisors %F A161707 a(n) = C(n,0) + 2*C(n,1) + 2*C(n,2) + 8*C(n,3). %e A161707 Differences of divisors of 21 to compute the coefficients of their interpolating polynomial, see formula: %e A161707 1 ... 3 ... 7 ... 21 %e A161707 .. 2 ... 4 .. 14 %e A161707 ..... 2 .. 10 %e A161707 ........ 8. %Y A161707 A005408, A000124, A016813, A086514, A000125, A058331, A002522, A161701, A161702, A161703, A000127, A161704, A161706, A161708, A161710, A080856, A161711, A161712, A161713, A161715, A006261. %Y A161707 Sequence in context: A036569 A018303 A098545 this_sequence A151267 A091489 A047087 %Y A161707 Adjacent sequences: A161704 A161705 A161706 this_sequence A161708 A161709 A161710 %K A161707 nonn %O A161707 0,2 %A A161707 Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Jun 17 2009 Search completed in 0.002 seconds