A242318 Number of length n+3+2 0..3 arrays with every value 0..3 appearing at least once in every consecutive 3+3 elements, and new values 0..3 introduced in order.
65, 185, 503, 1316, 3398, 8801, 23069, 60197, 156887, 408962, 1066514, 2781611, 7253453, 18914369, 49323167, 128621684, 335409314, 874649537, 2280834353, 5947765493, 15510073823, 40445831522, 105471145814, 275038567523
Offset: 1
Keywords
Examples
Some solutions for n=5: ..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0 ..0....0....1....1....0....1....0....1....1....0....1....1....1....1....1....1 ..0....1....0....2....1....1....1....2....1....1....2....2....2....1....2....2 ..1....2....1....0....2....2....2....3....2....2....3....0....0....2....3....3 ..2....3....2....3....0....3....3....1....3....3....2....3....1....1....0....1 ..3....0....3....3....3....0....2....2....0....1....0....2....3....3....1....1 ..1....1....0....1....2....1....0....0....1....0....3....2....2....0....3....0 ..3....1....2....2....1....2....3....2....0....2....1....1....0....1....1....2 ..0....2....1....0....3....1....1....3....2....3....0....2....2....2....2....0 ..3....0....1....0....2....3....1....0....2....0....0....0....3....3....3....3
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Crossrefs
Column 3 of A242322.
Formula
Empirical: a(n) = a(n-1) + 2*a(n-2) + 3*a(n-3) + 5*a(n-4) + 6*a(n-5) - a(n-6) - a(n-7) - a(n-9) - a(n-10).
Empirical g.f.: x*(65 + 120*x + 188*x^2 + 248*x^3 + 196*x^4 - 53*x^5 - 36*x^6 - 16*x^7 - 49*x^8 - 35*x^9) / (1 - x - 2*x^2 - 3*x^3 - 5*x^4 - 6*x^5 + x^6 + x^7 + x^9 + x^10). - Colin Barker, Nov 01 2018