A127322 - OEIS

%I #5 Jul 11 2015 16:56:33

%S 0,0,1,1,1,0,1,1,1,2,2,2,2,2,2,0,1,1,1,2,2,2,2,2,2,3,3,3,3,3,3,3,3,3,

%T 3,0,1,1,1,2,2,2,2,2,2,3,3,3,3,3,3,3,3,3,3,4,4,4,4,4,4,4,4,4,4,4,4,4,

%U 4,4,0,1,1,1,2,2,2,2,2,2,3,3,3,3,3,3,3,3,3,3,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4

%N Second 4-dimensional hyper-tetrahedral coordinate; 4-D analog of A056557.

%C If {(W,X,Y,Z)} are 4-tuples of nonnegative integers with W>=X>=Y>=Z ordered by W, X, Y and Z, then W=A127321(n), X=A127322(n), Y=A127323(n) and Z=A127324(n). These sequences are the four-dimensional analog of the three-dimensional A056556, A056557 and A056558.

%F For W>=X>=0, a(A000332(W+3)+A000292(X)) = a(A000332(W+3)+A000292(X+1)-1) = X A127322(n+1) = A127321(n)==A127324(n) ? 0 : A127322(n)==A127324(n) ? A127322(n)+1 : A127322(n)

%e a(23)=2 because a(A000332(2+3)+A000292(2)) = a(A000332(2+3)+A000292(3)-1) = 2, so a(19) = a(24) = 2.

%e See A127321 for a table of A127321, A127322, A127323, A127324.

%Y Cf. A127321, A127323, A127324, A056556, A056557, A056558, A000332, A000292, A000217.

%K nonn

%O 0,10

%A _Graeme McRae_, Jan 10 2007