A301907 Number of 3Xn 0..1 arrays with every element equal to 0, 2 or 3 horizontally or antidiagonally adjacent elements, with upper left element zero.
4, 1, 3, 2, 2, 7, 12, 27, 62, 160, 387, 951, 2362, 5895, 14745, 36892, 92334, 231171, 578926, 1450251, 3633632, 9105130, 22816655, 57178265, 143291478, 359102513, 899959089, 2255439374, 5652518690, 14166233267, 35503222896, 88977846175
Offset: 1
Keywords
Examples
All solutions for n=5 ..0..1..0..1..0. .0..1..1..1..1 ..0..1..0..1..0. .1..1..0..1..1 ..0..1..0..1..0. .1..1..1..1..0
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Crossrefs
Cf. A301906.
Formula
Empirical: a(n) = 2*a(n-1) +a(n-2) +3*a(n-4) -a(n-6) -4*a(n-7) -17*a(n-8) -30*a(n-9) -27*a(n-10) -36*a(n-11) -6*a(n-12) +4*a(n-13) +22*a(n-14) +36*a(n-15) +46*a(n-16) +32*a(n-17) +22*a(n-18) -4*a(n-19) -11*a(n-20) -6*a(n-21) -19*a(n-22) -4*a(n-23) -9*a(n-24) +4*a(n-25) -a(n-26) +4*a(n-27) -a(n-28) +2*a(n-29) -a(n-30) for n>31
Comments