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a(n) = (-1) * j((1 + sqrt(-A003173(n+2)))/2).
2

%I #45 Oct 03 2021 04:47:47

%S 0,3375,32768,884736,884736000,147197952000,262537412640768000

%N a(n) = (-1) * j((1 + sqrt(-A003173(n+2)))/2).

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/HeegnerNumber.html">Heegner Number</a> and <a href="http://mathworld.wolfram.com/j-Function.html">j-Function</a>

%F a(n) = A199743(n-1)^3 for n > 1.

%e j((1+sqrt( -3))/2) = 0.

%e j((1+sqrt( -7))/2) = -3375 = (-1) * 15^3.

%e j((1+sqrt( -11))/2) = -32768 = (-1) * 32^3.

%e j((1+sqrt( -19))/2) = -884736 = (-1) * 96^3.

%e j((1+sqrt( -43))/2) = -884736000 = (-1) * 960^3.

%e j((1+sqrt( -67))/2) = -147197952000 = (-1) * 5280^3.

%e j((1+sqrt(-163))/2) = -262537412640768000 = (-1) * 640320^3.

%Y Cf. A003173, A032354, A199743, A305475.

%K nonn,fini,full

%O 1,2

%A _Seiichi Manyama_, Jun 03 2018