Least number k such that 2*k+n | sigma(k) + sigma(k+n), -1 if such a number is unknown.

Terms

a(0) =672a(1) =12a(2) =42a(3) =748a(4) =75a(5) =364a(6) =5a(7) =332a(8) =45a(9) =10a(10) =13a(11) =112a(12) =312a(13) =26a(14) =30a(15) =3604a(16) =3a(17) =3952a(18) =21a(19) =3780a(20) =24a(21) =6a(22) =55906105a(23) =12000a(24) =3192a(25) =44a(26) =1098a(27) =40a(28) =11a(29) =32123069025