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a(n) is the smallest positive integer that can be expressed as the difference of two positive triangular numbers in at least n ways.
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%I #5 Apr 13 2020 19:47:03

%S 2,5,9,27,45,63,105,135,225,315,315,315,945,945,945,945,1575,1575,

%T 2835,2835,3465,3465,3465,3465,10395,10395,10395,10395,10395,10395,

%U 10395,10395,17325,17325,17325,17325,31185,31185,31185,31185,45045,45045,45045,45045

%N a(n) is the smallest positive integer that can be expressed as the difference of two positive triangular numbers in at least n ways.

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/TriangularNumber.html">Triangular Number</a>

%Y Cf. A000217, A038547, A052346, A053587, A136107, A136108, A214771, A334078.

%K nonn

%O 1,1

%A _Ilya Gutkovskiy_, Apr 13 2020