A190037 Number of nondecreasing arrangements of n+2 numbers in 0..5 with the last equal to 5 and each after the second equal to the sum of one or two of the preceding three.

8, 12, 16, 23, 33, 45, 57, 69, 81, 93, 105, 117, 129, 141, 153, 165, 177, 189, 201, 213, 225, 237, 249, 261, 273, 285, 297, 309, 321, 333, 345, 357, 369, 381, 393, 405, 417, 429, 441, 453, 465, 477, 489, 501, 513, 525, 537, 549, 561, 573, 585, 597, 609, 621, 633, 645

Offset

1,1

Comments

Column 5 of A190041.

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n) = 12*n - 27 for n>4.

Empirical: G.f.: x*(8 - 4*x + 3*x^3 + 3*x^4 + 2*x^5) / (1 - x)^2. a(n) = 2*a(n-1) - a(n-2) for n>2. - Colin Barker, May 04 2018

Example

All solutions for n=3:
..5....1....2....1....1....4....1....0....1....1....1....2....3....2....1....1
..5....5....3....2....2....5....2....5....4....3....2....3....5....5....1....4
..5....5....5....3....3....5....3....5....4....4....2....3....5....5....2....5
..5....5....5....3....4....5....5....5....5....5....3....5....5....5....3....5
..5....5....5....5....5....5....5....5....5....5....5....5....5....5....5....5

Crossrefs

Cf. A190041.

Sequence in context: A078609 A084809 A186407 * A110558 A298703 A273800

Adjacent sequences: A190034 A190035 A190036 * A190038 A190039 A190040

Keyword

nonn

Author

R. H. Hardin, May 04 2011

Status

approved