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 A190945 Number of permutations of the n*(n+1)/2 numbers (i copies of i | i=1..n), with no element equal to another within a distance of 1. 1
 1, 1, 10, 1074, 1637124, 45156692400, 27230193578558160, 420296434943941609215120, 190200071567439616748736269178720, 2843464512159537301384360263178682136716160, 1562137388408002436396705025296003247844758163480828800 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS Seiichi Manyama, Table of n, a(n) for n = 1..36 (a(1)-a(13) from R. H. Hardin). EXAMPLE All solutions for n=3 ..3....3....3....3....3....2....1....3....3....2 ..2....1....2....2....2....3....3....1....2....3 ..3....3....1....3....3....2....2....2....3....1 ..2....2....3....1....2....3....3....3....1....3 ..1....3....2....2....3....1....2....2....3....2 ..3....2....3....3....1....3....3....3....2....3 PROG (Maxima) a(n):=sum(p!*coeff(expand(product(sum(binomial(k-1, k-j)*(-1)^(k-j)* (t^j/j!), j, 1, k), k, 1, n)), t, p), p, n, n*(n+1)/2);  // Tani Akinari, Sep 15 2012 CROSSREFS Sequence in context: A225604 A208560 A263311 * A226553 A054609 A119045 Adjacent sequences:  A190942 A190943 A190944 * A190946 A190947 A190948 KEYWORD nonn AUTHOR R. H. Hardin May 24 2011 STATUS approved

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Last modified October 19 06:03 EDT 2018. Contains 316336 sequences. (Running on oeis4.)