A248465 Number of length 4+2 0..n arrays with no three consecutive terms having the sum of any two elements equal to twice the third

26, 144, 1436, 6040, 21182, 56782, 138534, 295078, 589916, 1082878, 1900666, 3161064, 5083368, 7857546, 11844802, 17344202, 24892396, 34927864, 48224830, 65403924, 87536430, 115449764, 150581308, 194049230, 247712034, 312987618

Offset

1,1

Comments

Row 4 of A248461

Links

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

Formula

Empirical: a(n) = -a(n-1) -a(n-2) +2*a(n-5) +3*a(n-6) +4*a(n-7) +3*a(n-8) +2*a(n-9) -3*a(n-11) -4*a(n-12) -6*a(n-13) -5*a(n-14) -5*a(n-15) +3*a(n-18) +2*a(n-19) +4*a(n-20) +a(n-21) -a(n-23) +2*a(n-25) +2*a(n-26) +5*a(n-27) +3*a(n-28) +5*a(n-29) -5*a(n-32) -3*a(n-33) -5*a(n-34) -2*a(n-35) -2*a(n-36) +a(n-38) -a(n-40) -4*a(n-41) -2*a(n-42) -3*a(n-43) +5*a(n-46) +5*a(n-47) +6*a(n-48) +4*a(n-49) +3*a(n-50) -2*a(n-52) -3*a(n-53) -4*a(n-54) -3*a(n-55) -2*a(n-56) +a(n-59) +a(n-60) +a(n-61)

Example

Some solutions for n=6
..2....0....4....4....3....3....1....2....3....1....4....4....2....3....1....5
..6....4....0....1....5....2....6....2....1....0....6....1....3....3....4....6
..2....6....3....1....5....3....0....1....0....6....1....1....2....4....3....0
..5....6....2....3....6....5....1....6....1....4....5....6....5....1....6....4
..6....3....6....1....1....0....1....0....4....1....0....3....1....5....6....3
..6....6....3....4....2....1....4....2....0....1....4....5....2....2....2....6

Crossrefs

Sequence in context: A331458 A238917 A200449 * A014552 A192289 A230906

Adjacent sequences: A248462 A248463 A248464 * A248466 A248467 A248468

Keyword

nonn

Author

R. H. Hardin, Oct 06 2014

Status

approved