A212835 T(n,k)=Number of 0..k arrays of length n+1 with 0 never adjacent to k.
2, 7, 2, 14, 17, 2, 23, 50, 41, 2, 34, 107, 178, 99, 2, 47, 194, 497, 634, 239, 2, 62, 317, 1106, 2309, 2258, 577, 2, 79, 482, 2137, 6306, 10727, 8042, 1393, 2, 98, 695, 3746, 14407, 35954, 49835, 28642, 3363, 2, 119, 962, 6113, 29114, 97127, 204994, 231521
Offset: 1
Examples
Some solutions for n=5 k=4 ..1....4....1....1....1....3....2....1....1....4....3....1....0....2....2....3 ..1....3....0....4....2....4....1....1....2....2....3....4....1....3....3....1 ..1....3....3....1....3....3....2....2....2....4....3....3....1....1....0....3 ..1....3....0....4....2....3....3....3....4....2....2....0....4....4....2....1 ..1....4....0....3....2....2....3....3....4....4....0....1....4....3....4....2 ..1....2....0....4....3....1....0....2....4....2....3....2....1....4....3....4
Links
- R. H. Hardin, Table of n, a(n) for n = 1..9999
Crossrefs
Formula
Empirical for column k: a(n) = k*a(n-1) +(k-1)*a(n-2)
Empirical for rows:
n=1: a(k) = k^2 + 2*k - 1
n=2: a(k) = k^3 + 3*k^2 - k - 1
n=3: a(k) = k^4 + 4*k^3 - 4*k + 1
n=4: a(k) = k^5 + 5*k^4 + 2*k^3 - 8*k^2 + k + 1
n=5: a(k) = k^6 + 6*k^5 + 5*k^4 - 12*k^3 - 3*k^2 + 6*k - 1
n=6: a(k) = k^7 + 7*k^6 + 9*k^5 - 15*k^4 - 13*k^3 + 15*k^2 - k - 1
n=7: a(k) = k^8 + 8*k^7 + 14*k^6 - 16*k^5 - 30*k^4 + 24*k^3 + 8*k^2 - 8*k + 1
Comments