Composite k such that (k+1) * Sum_{d|k} d/sigma(d) is an integer.

Terms

a(0) =39a(1) =215a(2) =623a(3) =1023a(4) =1343a(5) =1455a(6) =2303a(7) =2431a(8) =2519a(9) =9503a(10) =13039a(11) =13055a(12) =13319a(13) =23759a(14) =24479a(15) =29183a(16) =44863a(17) =58463a(18) =58559a(19) =82583a(20) =85359a(21) =87295a(22) =99863a(23) =123463a(24) =136079a(25) =144143a(26) =147455a(27) =154623a(28) =196095a(29) =273023