A249286 - OEIS

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

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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.