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a(n) = (n! - 2^n)/8, n >= 4.
1

%I #15 Sep 08 2022 08:45:28

%S 1,11,82,614,5008,45296,453472,4989344,59874688,778376576,10897284352,

%T 163459291904,2615348727808,44460928495616,800296713183232,

%U 15205637551038464,304112751021948928,6386367771463417856,140500090972200435712,3231502092360621031424

%N a(n) = (n! - 2^n)/8, n >= 4.

%H G. C. Greubel, <a href="/A123367/b123367.txt">Table of n, a(n) for n = 4..448</a>

%t Table[(n!-2^n)/8,{n,4,30}] (* _Harvey P. Dale_, Aug 19 2012 *)

%o (PARI) for(n=4,25, print1((n!-2^n)/8, ", ")) \\ _G. C. Greubel_, Oct 13 2017

%o (Magma) [(Factorial(n)-2^n)/8: n in [4..25]]; // _G. C. Greubel_, Oct 13 2017

%Y Cf. A123642.

%K nonn

%O 4,2

%A _Aminu Alhaji Ibrahim_, Oct 12 2006

%E Corrected and extended by _Harvey P. Dale_, Aug 19 2012