A200663 Number of 0..3 arrays x(0..n-1) of n elements with each no smaller than the sum of its three previous neighbors modulo 4.
4, 10, 26, 69, 175, 432, 1076, 2671, 6627, 16421, 40695, 100886, 250093, 619947, 1536810, 3809790, 9444489, 23412999, 58041252, 143885484, 356695266, 884255363, 2192088651, 5434237397, 13471597487, 33396394603, 82790419927, 205239329905
Offset: 1
Keywords
Examples
Some solutions for n=6 ..0....2....0....1....1....2....3....1....1....1....2....2....0....1....0....2 ..3....3....2....1....1....2....3....3....3....1....2....3....2....3....3....2 ..3....3....2....3....2....0....3....0....0....2....3....3....2....1....3....0 ..2....2....1....2....1....2....2....1....2....3....3....3....1....1....3....3 ..3....0....1....3....3....3....3....1....2....3....0....2....1....1....2....1 ..1....2....3....2....2....3....3....3....2....1....3....1....2....3....1....1
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Formula
Empirical: a(n) = 3*a(n-1) -a(n-3) -6*a(n-4) -2*a(n-5) +4*a(n-6) +10*a(n-7) +8*a(n-8) -4*a(n-9) -37*a(n-10) +12*a(n-11) +5*a(n-12) +27*a(n-13) +6*a(n-14) -10*a(n-15) -25*a(n-16) -a(n-17) +23*a(n-19) -7*a(n-20) -14*a(n-21) -9*a(n-22) +94*a(n-23) -90*a(n-24) -38*a(n-25) +88*a(n-26) -72*a(n-27) +64*a(n-28) +75*a(n-29) -94*a(n-30) -141*a(n-31) +114*a(n-32) +23*a(n-33) +71*a(n-34) -49*a(n-35) -58*a(n-36) -100*a(n-37) +48*a(n-38) +140*a(n-39) -56*a(n-40) +32*a(n-41) -43*a(n-42) +18*a(n-43) +6*a(n-44) -14*a(n-45) -10*a(n-46) -12*a(n-47) +27*a(n-48) -2*a(n-49) -4*a(n-50) +6*a(n-51) -6*a(n-52) -2*a(n-53) +3*a(n-54) +3*a(n-55) -2*a(n-56) -a(n-57) +5*a(n-58) -5*a(n-59) +2*a(n-63) -a(n-64)
Comments