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a(n) = 5^n * 4^(n^2).
2

%I #7 Oct 09 2016 13:55:14

%S 1,20,6400,32768000,2684354560000,3518437208883200000,

%T 73786976294838206464000000,24758800785707605497982484480000000,

%U 132922799578491587290380706028034457600000000

%N a(n) = 5^n * 4^(n^2).

%C Hankel transform of A130976 .

%H G. C. Greubel, <a href="/A135292/b135292.txt">Table of n, a(n) for n = 0..40</a>

%F a(n)=5^n*4^(n^2)=A000351(n)*A060757(n).

%t Table[5^n*4^(n^2), {n, 0, 10}] (* _G. C. Greubel_, Oct 09 2016 *)

%o (PARI) a(n)=5^n*4^(n^2) \\ _Charles R Greathouse IV_, Oct 09 2016

%K nonn,easy

%O 0,2

%A _Philippe Deléham_, Dec 04 2007