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 A271611 Number of ways to reciprocally link elements of an n X n X n triangular array with themselves or a neighbor, with no more than 2 elements linked to themselves. 0

%I

%S 1,3,17,114,240,2238,216318,5622392,20454036,970623228,1038614548176,

%T 131929454285752,1257138602103744,316487245419538728,

%U 3147612978951707912144,2069163709506683013857472,63184698521304672890081520,85953148896748583125564477008

%N Number of ways to reciprocally link elements of an n X n X n triangular array with themselves or a neighbor, with no more than 2 elements linked to themselves.

%C Column 2 of A271617.

%e Some solutions for n=4

%e .....6........5........0........0........5........5........0........5

%e ....5.1......2.6......4.3......4.3......2.0......2.5......5.0......2.6

%e ...2.0.0....5.0.1....5.5.0....5.4.3....6.4.3....5.2.5....2.4.3....4.3.1

%e ..4.3.4.3..2.0.4.3..2.2.4.3..2.0.4.3..0.1.4.3..2.0.2.0..4.3.4.3..0.0.4.3

%e Element moves: 0=itself 1=nw 2=ne 3=w 4=e 5=sw 6=se, reciprocals total 7

%Y Cf. A271617.

%K nonn

%O 1,2

%A _R. H. Hardin_, Apr 10 2016

%E a(15)-a(18) from _Alois P. Heinz_, Jun 15 2017

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Last modified June 12 16:18 EDT 2021. Contains 344959 sequences. (Running on oeis4.)