A241429 Number of n X 2 0..3 arrays with no element equal to one plus the sum of elements to its left or one plus the sum of elements above it or zero plus the sum of the elements diagonally to its northwest or one plus the sum of the elements antidiagonally to its northeast, modulo 4.
3, 5, 2, 3, 5, 6, 9, 10, 15, 21, 28, 38, 49, 67, 91, 122, 169, 226, 312, 423, 578, 791, 1075, 1471, 2003, 2732, 3731, 5080, 6941, 9457, 12908, 17609, 24015, 32776, 44699, 60991, 83206, 113499, 154866, 211239, 288211, 393168, 536370, 731761, 998249, 1361895
Offset: 1
Keywords
Examples
All solutions for n=4: ..3..3....2..2....3..3 ..3..2....2..0....3..2 ..2..0....2..0....2..0 ..2..0....2..0....3..3
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Crossrefs
Column 2 of A241435.
Formula
Empirical: a(n) = 2*a(n-1) - 2*a(n-3) + a(n-4) + a(n-5) - 2*a(n-6) + a(n-7) + a(n-8) - 2*a(n-9) + 2*a(n-10) - a(n-11) for n>13.
Empirical g.f.: x*(3 - x - 8*x^2 + 5*x^3 + 6*x^4 - 8*x^5 + 2*x^6 + 4*x^7 - 5*x^8 + 3*x^9 - 6*x^11 + 4*x^12) / ((1 - x)*(1 - x - x^2 + x^3 - x^5 + x^6 - x^8 + x^9 - x^10)). - Colin Barker, Oct 30 2018
Comments