# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/

Search: id:a130078
Showing 1-1 of 1

%I A130078 #7 Oct 02 2017 08:25:54
%S A130078 1,4,2,8,16,64,32,64,128,512,256,2048,8192,16384,4096,65536,32768,
%T A130078 131072,65536,262144,524288,2097152,1048576,2097152,4194304,16777216,
%U A130078 8388608,134217728,134217728,1073741824,134217728,536870912,2147483648
%N A130078 Largest 2^x dividing A001623(n), the number of reduced three-line Latin rectangles.
%H A130078 John Riordan, <a href="http://www.jstor.org/stable/2308187">A recurrence relation for three-line Latin rectangles</a>, Amer. Math. Monthly, 59 (1952), pp. 159-162.
%H A130078 D. S. Stones, <a href="http://www.combinatorics.org/ojs/index.php/eljc/article/view/v17i1a1/0">The many formulas for the number of Latin rectangles</a>, Electron. J. Combin 17 (2010), A1.
%H A130078 D. S. Stones and I. M. Wanless, <a href="http://dx.doi.org/10.1016/j.jcta.2009.03.019">Divisors of the number of Latin rectangles</a>, J. Combin. Theory Ser. A 117 (2010), 204-215.
%F A130078 a(n) = A006519(A001623(n)). - _Michel Marcus_, Oct 02 2017
%o A130078 (PARI) a001623(n) = n*(n-3)!*sum(i=0, n, sum(j=0, n-i, (-1)^j*binomial(3*i+j+2, j)<<(n-i-j)/(n-i-j)!)*i!);
%o A130078 a(n) = 2^valuation(a001623(n), 2); \\ _Michel Marcus_, Oct 02 2017
%Y A130078 Cf. A001623, A006519, A130077, A130079.
%K A130078 nonn
%O A130078 3,2
%A A130078 Douglas Stones (dssto1(AT)student.monash.edu.au), May 06 2007

# Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE