a(n) is the smallest number k such that sigma(k + 2n) = sigma(k) - 2n, or -1 if no such number exists.

A305718

a(n) is the smallest number k such that sigma(k + 2n) = sigma(k) - 2n, or -1 if no such number exists.

Terms

    a(0) =1a(1) =6976a(2) =15a(3) =35a(4) =39a(5) =51a(6) =95a(7) =831a(8) =45a(9) =88a(10) =63a(11) =222a(12) =135a(13) =37888a(14) =96a(15) =284a(16) =117a(17) =354a(18) =175a(19) =84a(20) =153a(21) =176a(22) =3893a(23) =267a(24) =210

External references