OFFSET
0,4
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..100 (terms 1..17 from R. J. Mathar)
R. J. Mathar, A class of multinomial permutations avoiding object clusters, vixra:1511.0015 (2015)
FORMULA
From Vaclav Kotesovec, Nov 24 2018: (Start)
Recurrence: 72*(2562500*n^6 - 28700000*n^5 + 132339375*n^4 - 325827750*n^3 + 454176325*n^2 - 335170330*n + 94842168)*a(n) = 3*(1601562500*n^10 - 21140625000*n^9 + 123391796875*n^8 - 423007187500*n^7 + 944775218750*n^6 - 1434958662500*n^5 + 1501190434375*n^4 - 1066734651000*n^3 + 489294264300*n^2 - 138373925520*n + 5253272832)*a(n-1) + 40*(2946875000*n^9 - 37425312500*n^8 + 202210281250*n^7 - 613007709375*n^6 + 1158238267500*n^5 - 1429774838250*n^4 + 1130386059700*n^3 - 439029380875*n^2 - 90639409450*n + 124751567448)*a(n-2) - 1440*(166562500*n^8 - 1865500000*n^7 + 8477778125*n^6 - 20572469375*n^5 + 30057234250*n^4 - 27819019325*n^3 + 13875953795*n^2 + 328927290*n - 3329053712)*a(n-3) - 5760*(15375000*n^7 - 133762500*n^6 + 442461250*n^5 - 764293375*n^4 + 806629450*n^3 - 482585405*n^2 + 27997588*n + 122388456)*a(n-4) + 6912*(2562500*n^6 - 13325000*n^5 + 27276875*n^4 - 32220250*n^3 + 22166825*n^2 - 3068430*n - 5777712)*a(n-5).
a(n) ~ 5^(4*n + 1/2) * n^(4*n) / (24^n * exp(4*n + 4)). (End)
EXAMPLE
Some solutions for n=3
..1....1....1....1....1....1....1....1....1....1....1....1....1....1....1....1
..2....2....2....2....2....2....2....2....2....2....2....2....2....2....2....2
..3....1....3....3....3....3....3....3....3....3....1....1....3....3....1....3
..2....2....2....2....1....2....2....2....1....1....2....3....2....2....3....2
..3....3....3....3....2....1....3....1....2....3....3....2....1....1....2....3
..1....2....1....2....3....2....1....3....3....1....1....1....3....2....3....2
..2....3....3....3....1....3....3....2....2....3....2....3....1....1....1....1
..1....1....1....1....3....1....1....3....1....2....3....2....3....3....2....2
..3....2....2....3....2....3....3....2....3....3....2....3....2....2....3....3
..1....3....1....1....3....1....2....3....2....1....3....1....3....1....1....1
..3....1....3....2....2....2....3....1....3....2....1....3....2....3....2....2
..1....3....2....1....3....3....2....3....1....3....3....2....1....2....3....3
..2....2....1....2....1....1....1....1....2....2....1....3....3....3....1....1
..3....1....2....1....2....2....2....2....1....1....3....2....2....1....2....3
..2....3....3....3....1....3....1....1....3....2....2....1....1....3....3....1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 21 2011
EXTENSIONS
a(0)=1 prepended by Seiichi Manyama, Nov 16 2018
STATUS
approved