A228215 Number of second differences of arrays of length n+2 of numbers in 0..5

21, 271, 2731, 23351, 176851, 1225631, 8006491, 50556551, 313882531, 1932641711, 11839990891, 72260648471, 439667406451, 2668522016831, 16163719991611, 97745259402791, 590286253682371, 3560791008422351, 21460113482174731

Offset

1,1

Comments

Column 5 of A228218

Links

R. H. Hardin, Table of n, a(n) for n = 1..189

Formula

Empirical: a(n) = 11*a(n-1) -30*a(n-2) for n>11

Example

Some solutions for n=4
..1....2...-1...-7...-4..-10...-6....1....2....8...-3....2...-6...-3....5....6
.-4....2...-3....5....0....8....5....2...-5...-2....1...-2....8....0...-3...-9
..1...-2...-1...-1....7...-3....2....0....4...-3....4....6...-1....3...-1....5
..5....3....6....2...-5...-2...-3....5....3....5...-8...-5...-5...-1....6....3

Crossrefs

Sequence in context: A215766 A320819 A360499 * A032535 A022745 A225967

Adjacent sequences: A228212 A228213 A228214 * A228216 A228217 A228218

Keyword

nonn

Author

R. H. Hardin Aug 16 2013

Status

approved