cp's OEIS Frontend

A271614 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 5 elements linked to themselves.

%I A271614 #7 Jun 18 2017 12:44:48
%S A271614 1,4,26,307,7764,222936,3243689,132728354,30892003921,3065366376540,
%T A271614 74672717363118,12952235029243936,25923218026065797712,
%U A271614 11188107558636007931696,695394278635888843298780,579704015638436450676621584,9319830273030294425399538816052
%N A271614 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 5 elements linked to themselves.
%C A271614 Column 5 of A271617.
%F A271614 a(n) = Sum_{i=0..2} A288852(n,floor(n*(n+1)/4)-i). - _Alois P. Heinz_, Jun 18 2017
%e A271614 Some solutions for n=4
%e A271614 .....5........0........6........0........0........0........5........5
%e A271614 ....2.0......0.0......0.1......4.3......4.3......0.5......2.5......2.0
%e A271614 ...4.3.5....4.3.5....0.4.3....4.3.6....0.4.3....0.2.5....5.2.5....0.0.6
%e A271614 ..0.0.2.0..4.3.2.0..0.4.3.0..0.0.0.1..0.0.4.3..4.3.2.0..2.0.2.0..0.4.3.1
%e A271614 Element moves: 0=itself 1=nw 2=ne 3=w 4=e 5=sw 6=se, reciprocals total 7
%Y A271614 Cf. A271617, A288852.
%K A271614 nonn
%O A271614 1,2
%A A271614 _R. H. Hardin_, Apr 10 2016
%E A271614 a(14)-a(17) from _Alois P. Heinz_, Jun 15 2017