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 A270256 T(n,k)=Number of nXnXn triangular 0..k arrays with some element plus some adjacent element totalling k exactly once. 12
 0, 0, 0, 0, 12, 0, 0, 24, 66, 0, 0, 48, 768, 468, 0, 0, 72, 4428, 37848, 3612, 0, 0, 108, 14976, 772056, 3280968, 40020, 0, 0, 144, 42750, 7876728, 308256072, 534438768, 601368, 0, 0, 192, 96768, 51535116, 12712991544, 302595682944, 168922341960 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,5 COMMENTS Table starts .0.....0.........0............0..............0................0 .0....12........24...........48.............72..............108 .0....66.......768.........4428..........14976............42750 .0...468.....37848.......772056........7876728.........51535116 .0..3612...3280968....308256072....12712991544.....233617868244 .0.40020.534438768.302595682944.67475902622400.4283012188676772 LINKS R. H. Hardin, Table of n, a(n) for n = 1..98 FORMULA Empirical for row n: n=2: a(n) = 2*a(n-1) -2*a(n-3) +a(n-4) n=3: [order 10] n=4: [order 18] Empirical quasipolynomials for row n: n=2: polynomial of degree 2 plus a quasipolynomial of degree 0 with period 2 n=3: polynomial of degree 5 plus a quasipolynomial of degree 3 with period 2 n=4: polynomial of degree 9 plus a quasipolynomial of degree 7 with period 2 EXAMPLE Some solutions for n=3 k=4 ....0......2......2......2......4......1......3......2......3......0......3 ...1.1....1.3....0.0....4.1....4.3....4.0....3.2....2.1....4.3....4.2....1.0 ..0.4.4..1.2.0..2.2.1..3.1.2..3.0.2..2.1.0..4.0.1..1.4.2..3.0.3..3.3.4..1.0.2 CROSSREFS Sequence in context: A242240 A225341 A004012 * A072837 A023917 A230926 Adjacent sequences:  A270253 A270254 A270255 * A270257 A270258 A270259 KEYWORD nonn,tabl AUTHOR R. H. Hardin, Mar 14 2016 STATUS approved

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Last modified February 20 22:51 EST 2019. Contains 320362 sequences. (Running on oeis4.)