A272243 - OEIS

A272243

a(n) is the smallest number greater than a(n-1) that is expressible as the sum of two positive integers x + y = a(n), so that (x, y, a(n)) is an abc-hit, in more ways than a(n-1).

%I #9 Apr 24 2016 12:46:01

%S 9,81,625,729,6561,15625,117649,390625

%N a(n) is the smallest number greater than a(n-1) that is expressible as the sum of two positive integers x + y = a(n), so that (x, y, a(n)) is an abc-hit, in more ways than a(n-1).

%C An abc-hit is a triple of coprime positive integers a, b, c such that a + b = c and rad(abc) < c, where rad(n) is the largest squarefree number dividing n.

%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Abc_conjecture">abc conjecture</a>

%Y Cf. A272242.

%Y Cf. A120498, A130510 (possible values of c in abc-hits).

%Y Cf. A225426 (triples of abc-hits).

%Y Cf. A130512 (radicals of abc-hits).

%Y Cf. A007947 (radicals).

%K nonn,more

%O 1,1

%A _Vladimir Letsko_, Apr 23 2016