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 A116220 If X_1,...,X_n is a partition of a 4n-set X into 4-blocks then a(n) is equal to the number of permutations f of X such that f(X_i) <> X_i, (i=1,...,n). 3
 0, 39744, 476126208, 20876944084992, 2430394026897309696, 620098244484731975761920, 304784138698487640049544331264, 263072308376236973471661993731555328, 371936496850567880606221498503260339699712, 815826011669313721421241471652159968573722198016 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS G. C. Greubel, Table of n, a(n) for n = 1..110 Milan Janjic, Enumerative Formulas for Some Functions on Finite Sets FORMULA a(n) = Sum_{j=0..n} (-24)^j*binomial(n,j)*(4*n-4*j)!. MAPLE a:=n->sum((-24)^i*binomial(n, i)*(4*n-4*i)!, i=0..n). MATHEMATICA Table[Sum[(-24)^j*Binomial[n, j]*(4*n-4*j)!, {j, 0, n}], {n, 1, 20}] (* G. C. Greubel, May 11 2019 *) PROG (PARI) {a(n) = sum(j=0, n, (-24)^j*binomial(n, j)*(4*(n-j))!)}; \\ G. C. Greubel, May 11 2019 (Magma) [(&+[(-24)^j*Binomial(n, j)*Factorial(4*n-4*j): j in [0..n]]): n in [1..20]]; // G. C. Greubel, May 11 2019 (Sage) [sum((-24)^j*binomial(n, j)*factorial(4*n-4*j) for j in (0..n)) for n in (1..20)] # G. C. Greubel, May 11 2019 (GAP) List([1..20], n-> Sum([0..n], j-> (-24)^j*Binomial(n, j)* Factorial(4*n-4*j))) # G. C. Greubel, May 11 2019 CROSSREFS Cf. A116218, A116219, A116221. Sequence in context: A204311 A235255 A234920 * A103809 A257192 A257185 Adjacent sequences: A116217 A116218 A116219 * A116221 A116222 A116223 KEYWORD nonn AUTHOR Milan Janjic, Apr 09 2007 STATUS approved

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Last modified September 22 05:50 EDT 2023. Contains 365519 sequences. (Running on oeis4.)