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A245996 Number of length 1+2 0..n arrays with no pair in any consecutive three terms totalling exactly n 1
2, 8, 28, 64, 126, 216, 344, 512, 730, 1000, 1332, 1728, 2198, 2744, 3376, 4096, 4914, 5832, 6860, 8000, 9262, 10648, 12168, 13824, 15626, 17576, 19684, 21952, 24390, 27000, 29792, 32768, 35938, 39304, 42876, 46656, 50654, 54872, 59320, 64000, 68922 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 1 of A245995

LINKS

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

FORMULA

Empirical: a(n) = 3*a(n-1) -2*a(n-2) -2*a(n-3) +3*a(n-4) -a(n-5).

Empirical: a(n) = 2*A036486(n). G.f.: 2*x*(1+x+4*x^2) / ( (1+x)*(x-1)^4 ). - R. J. Mathar, Aug 10 2014

EXAMPLE

Some solutions for n=10

..6....9....5....8....0....5....8....6....9....8....5....0....4....8....5....2

..3....8....3....0....0....7....9....5....0....4....7....5....2....4....7....6

..6....9....6....9....5....9....7....3....7....4....1....7...10....0....2....6

CROSSREFS

Sequence in context: A299640 A197932 A170871 * A229935 A082107 A135263

Adjacent sequences:  A245993 A245994 A245995 * A245997 A245998 A245999

KEYWORD

nonn

AUTHOR

R. H. Hardin, Aug 09 2014

STATUS

approved

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Last modified May 12 19:15 EDT 2021. Contains 343829 sequences. (Running on oeis4.)