A322093
Square array A(n,k), n >= 1, k >= 1, read by antidiagonals, where A(n,k) is the number of permutations of n copies of 1..k with no element equal to another within a distance of 1.
Original entry on oeis.org
1, 2, 0, 6, 2, 0, 24, 30, 2, 0, 120, 864, 174, 2, 0, 720, 39480, 41304, 1092, 2, 0, 5040, 2631600, 19606320, 2265024, 7188, 2, 0, 40320, 241133760, 16438575600, 11804626080, 134631576, 48852, 2, 0, 362880, 29083420800, 22278418248240, 131402141197200, 7946203275000, 8437796016, 339720, 2, 0
Offset: 1
Square array begins:
1, 2, 6, 24, 120, 720, ...
0, 2, 30, 864, 39480, 2631600, ...
0, 2, 174, 41304, 19606320, 16438575600, ...
0, 2, 1092, 2265024, 11804626080, 131402141197200, ...
0, 2, 7188, 134631576, 7946203275000, 1210527140790855600, ...
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Table[Table[SeriesCoefficient[1/(1 - Sum[x[i]/(1 + x[i]), {i, 1, n}]), Sequence @@ Table[{x[i], 0, k}, {i, 1, n}]],{n, 1, 6}], {k, 1, 5}] (* Zlatko Damijanic, Nov 03 2024 *)
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q(n,x) = sum(i=1, n, (-1)^(n-i) * binomial(n-1, n-i) * x^i/i!)
T(n,k) = subst(serlaplace(q(n,x)^k), x, 1) \\ Andrew Howroyd, Feb 03 2024
A190830
Number of permutations of 4 copies of 1..n introduced in order 1..n with no element equal to another within a distance of 1.
Original entry on oeis.org
1, 0, 1, 182, 94376, 98371884, 182502973885, 551248360550999, 2536823683737613858, 16904301142107043464659, 156690501089429126239232946, 1955972150994131850032960933480, 32016987304767134806200915633253966, 672058204939482014438623912695190927357
Offset: 0
Some solutions for n=3:
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2
3 1 3 3 1 3 3 3 3 3 3 1 1 3 1 1
1 2 2 2 2 2 2 1 1 2 1 3 3 1 3 2
2 3 3 3 1 1 3 2 2 3 2 1 2 3 1 1
3 2 1 2 3 2 1 3 1 1 3 2 3 2 2 3
1 3 2 3 2 3 3 1 3 2 2 3 2 1 3 1
3 2 3 1 3 1 2 3 1 1 1 2 1 3 2 3
1 1 1 3 1 3 1 2 2 3 3 3 2 2 3 2
2 3 2 1 3 2 3 1 3 1 1 2 3 3 1 3
3 1 1 2 2 3 1 3 2 2 2 3 1 1 3 2
2 3 3 1 3 1 2 2 3 3 3 1 3 2 2 3
A321634
Number of arrangements of n 1's, n 2's, ..., n n's avoiding equal consecutive terms.
Original entry on oeis.org
1, 1, 2, 174, 2265024, 7946203275000, 12229789732207993835280, 12202002913678756821228939869239920, 10937192762438008527903830198163831816546577931520, 11655577382287102750765311537460065620507094071664576111302628243840
Offset: 0
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{a(n) = sum(i=n, n^2, i!*polcoef(sum(j=1, n, (-1)^(n-j)*binomial(n-1, j-1)*x^j/j!)^n, i))} \\ Seiichi Manyama, May 27 2019
A330266
Number of ways to shuffle a deck of 4n cards, with 4 cards in each of n ranks, so that adjacent cards have different ranks.
Original entry on oeis.org
1, 0, 1152, 15095808, 751480602624, 93995798935633920, 25111340235557122867200, 12742555660097789273088983040, 11259023892340311657074592904642560, 16205462460428776872054787528078739374080, 36051066700209244649349258741114804984663244800, 118807003903158552156678227915553602167323425243136000
Offset: 0
a(13) = 3668033946384704437729512814619767610579526911188666362431432294400 is the number of ways to shuffle a standard 52-card deck of playing cards so that no two cards of the same rank are adjacent.
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Table[Integrate[(x^4 - 12x^3 + 36x^2 - 24x)^n *Exp[-x],{x,0,Infinity}],{n,0,10}] (* Stefano Spezia, Dec 09 2019 *)
Showing 1-4 of 4 results.