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 A199900 Number of -n..n arrays x(0..4) of 5 elements with zero sum, and adjacent elements not both strictly positive and not both strictly negative. 1
 33, 159, 461, 1043, 2031, 3573, 5839, 9021, 13333, 19011, 26313, 35519, 46931, 60873, 77691, 97753, 121449, 149191, 181413, 218571, 261143, 309629, 364551, 426453, 495901, 573483, 659809, 755511, 861243, 977681, 1105523, 1245489, 1398321 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Row 5 of A199898. LINKS R. H. Hardin, Table of n, a(n) for n = 1..200 FORMULA Empirical: a(n) = (11/12)*n^4 + (49/6)*n^3 + (193/12)*n^2 + (41/6)*n + 1. Conjectures from Colin Barker, May 16 2018: (Start) G.f.: x*(33 - 6*x - 4*x^2 - 2*x^3 + x^4) / (1 - x)^5. a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5) for n>5. (End) EXAMPLE Some solutions for n=6: .-4...-2....0....2....0....2....0....0...-5....2...-1...-2...-4....3...-6...-6 ..3....2....3...-4....1...-3...-3....6....5...-1....4....0....6...-6....1....6 .-1...-1...-5....0....0....3....6....0...-3....1...-3....5...-1....2...-1...-1 ..6....5....0...-2....5...-3...-3...-6....5...-5....5....0....1...-3....6....4 .-4...-4....2....4...-6....1....0....0...-2....3...-5...-3...-2....4....0...-3 CROSSREFS Cf. A199898. Sequence in context: A005904 A207078 A182588 * A086504 A233064 A183776 Adjacent sequences: A199897 A199898 A199899 * A199901 A199902 A199903 KEYWORD nonn AUTHOR R. H. Hardin, Nov 11 2011 STATUS approved

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Last modified November 30 21:57 EST 2022. Contains 358453 sequences. (Running on oeis4.)