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 A185970 a(n) = 2^((n^2-n-2)/2)*(n+2)! 1
 1, 3, 24, 480, 23040, 2580480, 660602880, 380507258880, 487049291366400, 1371530804487782400, 8426685262772935065600, 112176034218033311593267200, 3216311253099451110002157158400, 197610163390430276198532535812096000, 25901159335910477161894056533963046912000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS a(n) is the determinant of the symmetric matrix (if(j<=floor((i+j)/2), 2^k*(k+1), 2^n*(n+1)))_{0<=i,j<=n}. LINKS G. C. Greubel, Table of n, a(n) for n = 0..77 FORMULA a(n) = 2^binomial(n,2)*A001710(n+2). a(n) = 2^binomial(n+1,2)*Product_{k=0..n} (k+2)/2} = Product_{k=0..n} 2^k*(k+2)/2. EXAMPLE a(3)=280 since det[1, 1, 1, 1; 1, 4, 4, 4; 1, 4, 12, 12; 1, 4, 12, 32]=280. MATHEMATICA Table[2^((n^2 - n - 2)/2)*(n + 2)!, {n, 0, 50}] (* G. C. Greubel, Jul 23 2017 *) PROG (PARI) for(n=0, 50, print1(2^((n^2 - n - 2)/2)*(n + 2)!, ", ")) \\ G. C. Greubel, Jul 23 2017 CROSSREFS Cf. A001787. Sequence in context: A002832 A233151 A236466 * A279165 A336577 A194157 Adjacent sequences:  A185967 A185968 A185969 * A185971 A185972 A185973 KEYWORD nonn,easy AUTHOR Paul Barry, Feb 16 2011 STATUS approved

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Last modified May 12 23:35 EDT 2021. Contains 343829 sequences. (Running on oeis4.)