A201090 Number of -n..n arrays of 5 elements with first and second differences also in -n..n

47, 537, 2771, 9593, 25935, 59533, 121371, 226521, 394443, 649989, 1023515, 1552101, 2279419, 3257221, 4544919, 6211381, 8334179, 11001745, 14312231, 18376077, 23314439, 29262209, 36365967, 44787505, 54701247, 66298329, 79783443

Offset

1,1

Comments

Row 5 of A201088

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +2*a(n-2) -5*a(n-3) -2*a(n-4) +4*a(n-5) +4*a(n-6) -2*a(n-7) -5*a(n-8) +2*a(n-9) +2*a(n-10) -a(n-11).

Empirical: -x*(-47 -443*x -1603*x^2 -3212*x^3 -3986*x^4 -3218*x^5 -1606*x^6 -436*x^7 -47*x^8 -3*x^9 +x^10) / ( (1+x+x^2)*(1+x)^3*(x-1)^6 ). - R. J. Mathar, Nov 27 2011

Example

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

Crossrefs

Sequence in context: A106104 A009086 A034779 * A293368 A116146 A142253

Adjacent sequences: A201087 A201088 A201089 * A201091 A201092 A201093

Keyword

nonn

Author

R. H. Hardin Nov 26 2011

Status

approved