Square array A(n,k), n >= 1, k >= 0, read by antidiagonals: A(n,k) = Sum_{d|n} d*sigma_k(d).

Terms

a(0) =1a(1) =1a(2) =5a(3) =1a(4) =7a(5) =7a(6) =1a(7) =11a(8) =13a(9) =17a(10) =1a(11) =19a(12) =31a(13) =35a(14) =11a(15) =1a(16) =35a(17) =85a(18) =95a(19) =31a(20) =35a(21) =1a(22) =67a(23) =247a(24) =311a(25) =131a(26) =91a(27) =15a(28) =1a(29) =131