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 A248539 Number of length 2+3 0..n arrays with every four consecutive terms having the sum of some three elements equal to three times the fourth 1
 2, 15, 52, 113, 246, 427, 704, 1113, 1654, 2279, 3072, 4045, 5210, 6555, 8116, 9953, 12054, 14383, 16976, 19929, 23194, 26735, 30636, 34993, 39686, 44751, 50212, 56201, 62646, 69451, 76712, 84609, 93010, 101879, 111252, 121321, 131942, 143103, 154840 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Row 2 of A248537 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-4) +a(n-7) +a(n-8) -a(n-9) +a(n-10) -a(n-12) -a(n-13) -a(n-15) -a(n-16) +a(n-18) -a(n-19) +a(n-20) +a(n-21) +a(n-24) -a(n-26) +a(n-27) -a(n-28) Empirical also a cubic polynomial plus a linear quasipolynomial with period 360, the first 12 being: Empirical for n mod 360 = 0: a(n) = (11/4)*n^3 - (113/20)*n^2 + (97/10)*n + 1 Empirical for n mod 360 = 1: a(n) = (11/4)*n^3 - (113/20)*n^2 + (209/20)*n - (111/20) Empirical for n mod 360 = 2: a(n) = (11/4)*n^3 - (113/20)*n^2 + (97/10)*n - (19/5) Empirical for n mod 360 = 3: a(n) = (11/4)*n^3 - (113/20)*n^2 + (149/20)*n + (25/4) Empirical for n mod 360 = 4: a(n) = (11/4)*n^3 - (113/20)*n^2 + (97/10)*n - (57/5) Empirical for n mod 360 = 5: a(n) = (11/4)*n^3 - (113/20)*n^2 + (209/20)*n - (35/4) Empirical for n mod 360 = 6: a(n) = (11/4)*n^3 - (113/20)*n^2 + (97/10)*n - (109/5) Empirical for n mod 360 = 7: a(n) = (11/4)*n^3 - (113/20)*n^2 + (149/20)*n - (291/20) Empirical for n mod 360 = 8: a(n) = (11/4)*n^3 - (113/20)*n^2 + (97/10)*n - 11 Empirical for n mod 360 = 9: a(n) = (11/4)*n^3 - (113/20)*n^2 + (209/20)*n + (257/20) Empirical for n mod 360 = 10: a(n) = (11/4)*n^3 - (113/20)*n^2 + (97/10)*n - 3 Empirical for n mod 360 = 11: a(n) = (11/4)*n^3 - (113/20)*n^2 + (149/20)*n + (269/20) EXAMPLE Some solutions for n=6 ..0....3....5....2....2....2....5....0....0....6....6....1....2....4....6....0 ..1....5....6....3....2....2....4....6....3....1....0....5....3....5....2....6 ..2....4....5....1....4....3....3....6....2....4....0....6....6....5....4....3 ..1....0....4....6....0....5....4....4....3....5....2....4....1....6....4....3 ..4....3....1....2....2....2....5....0....0....6....6....5....2....4....6....0 CROSSREFS Sequence in context: A066562 A073877 A248538 * A248540 A007972 A248541 Adjacent sequences: A248536 A248537 A248538 * A248540 A248541 A248542 KEYWORD nonn AUTHOR R. H. Hardin, Oct 08 2014 STATUS approved

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Last modified January 30 15:58 EST 2023. Contains 359945 sequences. (Running on oeis4.)