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a(n) = 4^n*hypergeom([-n/4, (1-n)/4, (2-n)/4, (3-n)/4], [1, 1, 1], -1).
2

%I #12 Aug 06 2018 05:34:45

%S 1,4,16,64,232,544,-1664,-37376,-362024,-2743712,-17780864,-98955776,

%T -442825664,-1129423616,5536033792,118591811584,1224814969816,

%U 9905491019104,68032143081856,398051159254528,1854461906222272,4784426026102528

%N a(n) = 4^n*hypergeom([-n/4, (1-n)/4, (2-n)/4, (3-n)/4], [1, 1, 1], -1).

%C Diagonal of rational function 1/(1 - (x^4 + y^4 + z^4 - t^4 + 4*x*y*z*t)). - _Gheorghe Coserea_, Aug 04 2018

%F Let H(m, n, x) = m^n*hypergeom([(k-n)/m for k=0..m-1], [1 for k=0..m-2], x) then a(n) = H(4, n, -1).

%p T := (m,n,x) -> m^n*hypergeom([seq((k-n)/m, k=0..m-1)], [seq(1, k=0..m-2)], x):

%p lprint(seq(simplify(T(4,n,-1)), n=0..39));

%t Table[4^n * HypergeometricPFQ[{-n/4, (1-n)/4, (2-n)/4, (3-n)/4}, {1, 1, 1}, -1], {n, 0, 20}] (* _Vaclav Kotesovec_, Nov 02 2017 *)

%Y H(1, n, 1) = A000007(n), H(2, n, 1) = A000984(n), H(3, n, 1) = A006077(n), H(4, n, 1) = A294036(n), H(1, n, -1) = A000079(n), H(2, n, -1) = A098335(n), H(3, n, -1) = A294035(n), H(4, n, -1) = this seq..

%K sign

%O 0,2

%A _Peter Luschny_, Nov 02 2017