A246888 Number of length n+4 0..4 arrays with some pair in every consecutive five terms totalling exactly 4.
2701, 12481, 57585, 264981, 1216081, 5592169, 25710385, 118192273, 543322645, 2497751105, 11482493485, 52786380721, 242665353541, 1115563238521, 5128382983861, 23575813154485, 108380944031221, 498240685840957
Offset: 1
Keywords
Examples
Some solutions for n=3 ..4....4....4....1....4....4....1....4....4....1....4....4....0....3....3....2 ..3....4....3....0....4....3....1....1....4....1....3....4....2....1....2....3 ..2....4....1....1....3....0....4....4....2....4....4....0....0....2....3....2 ..2....3....4....2....0....4....3....2....1....3....2....1....4....4....1....4 ..3....0....0....2....4....2....1....2....2....4....1....0....3....1....3....1 ..0....0....3....2....0....0....3....3....3....2....1....4....0....2....4....0 ..3....2....0....4....3....0....3....4....1....0....0....0....2....1....1....4
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Formula
Empirical: a(n) = 3*a(n-1) +6*a(n-2) +5*a(n-3) +17*a(n-4) -16*a(n-5) -117*a(n-6) -174*a(n-7) -295*a(n-8) -478*a(n-9) +437*a(n-10) +1237*a(n-11) +663*a(n-12) +1581*a(n-13) +2542*a(n-14) -1551*a(n-15) -2164*a(n-16) -1754*a(n-17) -1473*a(n-18) +623*a(n-19) +1190*a(n-20) +651*a(n-21) +184*a(n-22) -263*a(n-23) -141*a(n-24) -109*a(n-25) -11*a(n-26) +46*a(n-27) +9*a(n-28) +10*a(n-29) +2*a(n-30) -3*a(n-31)
Comments