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

1,1

Comments

Column 4 of A249290.

Links

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

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).

Example

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

Crossrefs

Cf. A249290.

Sequence in context: A207199 A045209 A074889 * A283345 A125012 A281549

Adjacent sequences: A249283 A249284 A249285 * A249287 A249288 A249289

Keyword

nonn

Author

R. H. Hardin, Oct 24 2014

Status

approved