A189322 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 four.

8, 12, 21, 33, 54, 84, 119, 157, 195, 233, 271, 309, 347, 385, 423, 461, 499, 537, 575, 613, 651, 689, 727, 765, 803, 841, 879, 917, 955, 993, 1031, 1069, 1107, 1145, 1183, 1221, 1259, 1297, 1335, 1373, 1411, 1449, 1487, 1525, 1563, 1601, 1639, 1677, 1715

Offset

1,1

Comments

Column 5 of A189326.

Links

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

Formula

Empirical: a(n) = 38*n - 147 for n>6.

Empirical g.f.: x*(8 - 4*x + 5*x^2 + 3*x^3 + 9*x^4 + 9*x^5 + 5*x^6 + 3*x^7) / (1 - x)^2. - Colin Barker, May 02 2018

Example

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

Crossrefs

Cf. A189326.

Sequence in context: A300065 A072902 A269705 * A105571 A350633 A141616

Adjacent sequences: A189319 A189320 A189321 * A189323 A189324 A189325

Keyword

nonn

Author

R. H. Hardin, Apr 20 2011

Status

approved