cp's OEIS Frontend

A222387 Sum of neighbor maps: number of 2Xn binary arrays indicating the locations of corresponding elements equal to the sum mod 3 of their horizontal and antidiagonal neighbors in a random 0..2 2Xn array.

%I A222387 #6 Jul 23 2025 02:33:43
%S A222387 4,16,48,248,1024,3968,15872,65536,262144,1048576,4177632,16777216,
%T A222387 67108864,268435456,1073479680,4294961152,17179869184,68719378432,
%U A222387 274872664064,1099511627776,4398046511104,17592186044416,70368641459200
%N A222387 Sum of neighbor maps: number of 2Xn binary arrays indicating the locations of corresponding elements equal to the sum mod 3 of their horizontal and antidiagonal neighbors in a random 0..2 2Xn array.
%C A222387 Row 2 of A222386
%H A222387 R. H. Hardin, <a href="/A222387/b222387.txt">Table of n, a(n) for n = 1..210</a>
%F A222387 Empirical: a(n) = 4*a(n-1) +32*a(n-4) -128*a(n-5) -256*a(n-8) +1024*a(n-9) +592*a(n-12) -2368*a(n-13) -18944*a(n-16) +75776*a(n-17) +151552*a(n-20) -606208*a(n-21) -109056*a(n-24) +436224*a(n-25) +3489792*a(n-28) -13959168*a(n-29) -27918336*a(n-32) +111673344*a(n-33) +6594560*a(n-36) -26378240*a(n-37) -211025920*a(n-40) +844103680*a(n-41) +1688207360*a(n-44) -6752829440*a(n-45) -189071360*a(n-48) +756285440*a(n-49) +6050283520*a(n-52) -24201134080*a(n-53) -48402268160*a(n-56) +193609072640*a(n-57) +2853175296*a(n-60) -11412701184*a(n-61) -91301609472*a(n-64) +365206437888*a(n-65) +730412875776*a(n-68) -2921651503104*a(n-69) -22011707392*a(n-72) +88046829568*a(n-73) +704374636544*a(n-76) -2817498546176*a(n-77) -5634997092352*a(n-80) +22539988369408*a(n-81) +68719476736*a(n-84) -274877906944*a(n-85) -2199023255552*a(n-88) +8796093022208*a(n-89) +17592186044416*a(n-92) -70368744177664*a(n-93)
%e A222387 Some solutions for n=3
%e A222387 ..1..1..0....0..0..1....1..1..0....0..1..1....1..1..1....0..0..1....0..0..0
%e A222387 ..1..0..0....1..1..0....1..1..1....0..1..0....0..0..0....0..0..0....1..0..0
%K A222387 nonn
%O A222387 1,1
%A A222387 _R. H. Hardin_ Feb 18 2013