A303521 Number of nX4 0..1 arrays with every element equal to 0, 1, 3, 4, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.
5, 21, 37, 103, 340, 1115, 4112, 16640, 71025, 320957, 1510853, 7287031, 35723065, 176869202, 880763327, 4401181230, 22037652351, 110478062574, 554227859714, 2781487076749, 13962670138510, 70100301160570, 351970530142109
Offset: 1
Keywords
Examples
Some solutions for n=5 ..0..1..0..0. .0..1..1..1. .0..0..0..1. .0..1..1..0. .0..1..1..0 ..0..0..1..0. .0..1..0..1. .0..1..1..1. .0..1..0..1. .1..0..1..0 ..1..1..1..1. .0..1..0..1. .0..1..0..1. .0..1..0..1. .1..0..1..0 ..1..0..1..1. .0..1..1..1. .0..0..0..1. .0..1..0..1. .1..0..1..0 ..1..0..1..0. .0..1..0..0. .0..1..0..1. .0..1..0..1. .1..0..1..0
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Crossrefs
Cf. A303525.
Formula
Empirical: a(n) = 7*a(n-1) -9*a(n-2) +8*a(n-3) -68*a(n-4) +8*a(n-5) -6*a(n-6) +260*a(n-7) +444*a(n-8) +617*a(n-9) -488*a(n-10) -858*a(n-11) -2426*a(n-12) -1778*a(n-13) -2233*a(n-14) +1090*a(n-15) +2944*a(n-16) +5714*a(n-17) +4242*a(n-18) +1676*a(n-19) -5030*a(n-20) -6560*a(n-21) -3203*a(n-22) +5344*a(n-23) +11678*a(n-24) +10874*a(n-25) +8003*a(n-26) -6178*a(n-27) -11743*a(n-28) -18221*a(n-29) -11933*a(n-30) -7346*a(n-31) +3388*a(n-32) +8166*a(n-33) +9709*a(n-34) +6270*a(n-35) +2172*a(n-36) -1377*a(n-37) -2343*a(n-38) -1877*a(n-39) -576*a(n-40) +51*a(n-41) +210*a(n-42) +170*a(n-43) +22*a(n-44) -13*a(n-45) -31*a(n-46) -9*a(n-47) for n>49
Comments