A249286 Number of length n+3 0..4 arrays with no four consecutive terms having the sum of any three elements equal to three times the fourth.

524, 2228, 9504, 40588, 173368, 740616, 3164312, 13520668, 57772560, 246857788, 1054810472, 4507167504, 19258980852, 82293014888, 351635522044, 1502528043892, 6420257600360, 27433569837528, 117222829267252

Offset: 1

Author

R. H. Hardin, Oct 24 2014

Keywords

• nonn

Comments

Column 4 of A249290.

Examples

			Some solutions for n=5
..2....0....0....1....1....2....2....1....1....1....0....2....0....0....0....0
..3....4....3....0....1....0....1....2....0....2....2....1....2....3....1....2
..1....4....1....4....2....0....0....1....0....4....0....4....2....2....1....2
..0....0....3....4....3....0....3....3....2....3....0....2....3....1....4....0
..3....4....2....1....3....4....4....0....3....2....1....4....3....4....0....0
..2....0....4....4....1....3....3....4....4....2....4....3....3....2....4....1
..0....3....2....4....4....2....0....0....2....0....4....0....1....2....4....1
..2....2....3....2....1....2....3....1....0....3....1....3....3....1....4....0
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..210

Crossrefs

Cf. A249290.

Formula

Empirical: a(n) = 3*a(n-1) +3*a(n-2) +9*a(n-3) +35*a(n-4) -65*a(n-5) -151*a(n-6) -317*a(n-7) -534*a(n-8) -140*a(n-9) +1280*a(n-10) +2126*a(n-11) +2048*a(n-12) +5830*a(n-13) +4946*a(n-14) +11778*a(n-15) +25333*a(n-16) +19483*a(n-17) -11542*a(n-18) -9074*a(n-19) -7639*a(n-20) -13027*a(n-21) +38961*a(n-22) -25267*a(n-23) -187805*a(n-24) -120777*a(n-25) +143132*a(n-26) +88370*a(n-27) -57497*a(n-28) -100517*a(n-29) -152210*a(n-30) -3304*a(n-31) +156512*a(n-32) +254068*a(n-33) +111836*a(n-34) -84272*a(n-35) -31976*a(n-36) +9504*a(n-37) -3632*a(n-38) -144*a(n-39) +576*a(n-40).