Smallest k such that sigma(n+k) = sigma(k).

Terms

a(0) =1a(1) =14a(2) =33a(3) =382a(4) =51a(5) =6a(6) =20a(7) =10a(8) =15a(9) =14a(10) =21a(11) =28a(12) =35a(13) =182a(14) =24a(15) =26a(16) =30a(17) =142a(18) =40a(19) =34a(20) =42a(21) =20a(22) =57a(23) =135a(24) =70a(25) =30a(26) =99a(27) =42a(28) =66a(29) =406