cp's OEIS Frontend

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.

%I A271611 #6 Jun 15 2017 21:47:49
%S A271611 1,3,17,114,240,2238,216318,5622392,20454036,970623228,1038614548176,
%T A271611 131929454285752,1257138602103744,316487245419538728,
%U A271611 3147612978951707912144,2069163709506683013857472,63184698521304672890081520,85953148896748583125564477008
%N 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.
%C A271611 Column 2 of A271617.
%e A271611 Some solutions for n=4
%e A271611 .....6........5........0........0........5........5........0........5
%e A271611 ....5.1......2.6......4.3......4.3......2.0......2.5......5.0......2.6
%e A271611 ...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 A271611 ..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 A271611 Element moves: 0=itself 1=nw 2=ne 3=w 4=e 5=sw 6=se, reciprocals total 7
%Y A271611 Cf. A271617.
%K A271611 nonn
%O A271611 1,2
%A A271611 _R. H. Hardin_, Apr 10 2016
%E A271611 a(15)-a(18) from _Alois P. Heinz_, Jun 15 2017