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 A221460 Number of 0..n arrays of length n with each element unequal to at least one neighbor, starting with 0 2
 0, 2, 9, 80, 875, 11880, 192080, 3608576, 77295141, 1860100000, 49701143855, 1460328321024, 46805373800640, 1625353003293824, 60796114850390625, 2437185999638364160, 104248664384022862523, 4739500894223556407808 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Diagonal of A221463. LINKS R. H. Hardin, Table of n, a(n) for n = 1..71 FORMULA a(n) = [x^n] 1/(1 - x*Sum_{k>=1} n^k*x^k). - Ilya Gutkovskiy, Mar 21 2018 EXAMPLE Some solutions for n=6 ..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0 ..2....4....5....6....4....1....3....4....1....2....5....5....2....6....2....3 ..3....0....5....0....3....5....1....1....2....2....3....4....3....4....3....4 ..6....3....2....1....1....6....2....2....6....4....6....5....4....1....6....1 ..2....6....3....0....3....4....6....3....3....0....1....1....2....2....5....5 ..0....2....2....1....6....1....1....6....1....4....4....5....4....5....2....3 CROSSREFS Cf. A221463. Sequence in context: A194471 A369712 A215629 * A122720 A109519 A193208 Adjacent sequences: A221457 A221458 A221459 * A221461 A221462 A221463 KEYWORD nonn AUTHOR R. H. Hardin Jan 17 2013 STATUS approved

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Last modified August 6 07:30 EDT 2024. Contains 374960 sequences. (Running on oeis4.)