A212786 Half the number of 0..n arrays of length 7 with second differences nonzero

21, 397, 4379, 22972, 91482, 284360, 764297, 1797975, 3883755, 7729696, 14517156, 25811656, 44024953, 72163603, 114677011, 176842932, 266174946, 391374778, 564396617, 798717009, 1112552471, 1525915970, 2065331568, 2759616340

Offset

1,1

Comments

Row 5 of A212782

Links

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

Formula

Empirical: a(n) = -a(n-1) -a(n-2) +a(n-3) +4*a(n-4) +6*a(n-5) +7*a(n-6) +a(n-7) -6*a(n-8) -16*a(n-9) -20*a(n-10) -16*a(n-11) -2*a(n-12) +18*a(n-13) +32*a(n-14) +38*a(n-15) +24*a(n-16) +2*a(n-17) -27*a(n-18) -43*a(n-19) -43*a(n-20) -27*a(n-21) +2*a(n-22) +24*a(n-23) +38*a(n-24) +32*a(n-25) +18*a(n-26) -2*a(n-27) -16*a(n-28) -20*a(n-29) -16*a(n-30) -6*a(n-31) +a(n-32) +7*a(n-33) +6*a(n-34) +4*a(n-35) +a(n-36) -a(n-37) -a(n-38) -a(n-39)

Example

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

Crossrefs

Sequence in context: A094172 A296723 A145613 * A015677 A285396 A113363

Adjacent sequences: A212783 A212784 A212785 * A212787 A212788 A212789

Keyword

nonn

Author

R. H. Hardin May 27 2012

Status

approved