Search: id:A001710 Results 1-1 of 1 results found. %I A001710 M2933 N1179 %S A001710 1,1,1,3,12,60,360,2520,20160,181440,1814400,19958400,239500800, %T A001710 3113510400,43589145600,653837184000,10461394944000,177843714048000, %U A001710 3201186852864000,60822550204416000,1216451004088320000 %N A001710 Order of alternating group A_n, or number of even permutations of n letters. %C A001710 For n >= 3, a(n-1) is also the number of ways that a 3-cycle in the symmetric group S_n can be written as a product of 2 long cycles (of length n). - Ahmed Fares (ahmedfares(AT)my-deja.com), Aug 14 2001 %C A001710 a(n) is the number of Hamiltonian circuit masks for an n X n adjacency matrix of an undirected graph. - Chad R. Brewbaker (crb002(AT)iastate.edu), Jan 31 2003 %C A001710 a(n) is the number of necklaces one can make with n distinct beads: n! bead permutations, divide by two to represent flipping the necklace over, divide by n to represent rotating the necklace. Related to Stirling numbers of the first kind, Stirling cycles. - Chad R. Brewbaker (crb002(AT)iastate.edu), Jan 31 2003 %C A001710 Number of increasing runs in all permutations of [n-1] (n>=2). Example: a(4)=12 because we have 12 increasing runs in all the permutations of [3] (shown in parentheses): (123), (13)(2), (3)(12), (2)(13), (23)(1), (3)(2)(1). - Emeric Deutsch (deutsch(AT)duke.poly.edu), Aug 28 2004 %C A001710 Minimum permanent over all n X n (0,1)-matrices with exactly n/2 zeros. - Simone Severini (ss54(AT)york.ac.uk), Oct 15 2004 %C A001710 Comment from John Perry, Sep 20 2008: The number of permutations of 1..n that have 2 following 1 for n >= 1 is 0,1,3,12,60,360,2520,20160, ... . %C A001710 Starting (1, 3, 12, 60,...) = binomial transform of A000153: (1, 2, 7, 32, 181,...). [From Gary W. Adamson (qntmpkt(AT)yahoo.com), Dec 25 2008] %C A001710 First column of A092582. [From Mats Granvik (mats.granvik(AT)abo.fi), Feb 08 2009] %C A001710 Contribution from Johannes W. Meijer (meijgia(AT)hotmail.com), Oct 20 2009: (Start) %C A001710 The asymptotic expansion of the higher order exponential integral E(x, m=1,n=3) ~ exp(-x)/x*(1 - 3/x + 12/x^2 - 60/x^3 + 360/x^4 - 2520/ x^5 + 20160/x^6 - 81440/x^7 + ...) leads to the sequence given above. See A163931 and A130534 for more information. %C A001710 (End) %D A001710 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %D A001710 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence). %D A001710 Mitrinovic, D. S.; Mitrinovic, R. S.; Tableaux d'une classe de nombres relies aux nombres de Stirling. Univ. Beograd. Publ. Elektrotehn. Fak. Ser. Mat. Fiz. No. 77 1962, 77 pp. %D A001710 J. Riordan, An Introduction to Combinatorial Analysis, Wiley, 1958, p. 88. %D A001710 S-Z Song, S-G Hwang, S-H Rim, G-S Cheon, Extremes of permanents of (0, 1)-matrices. Special issue on the Combinatorial Matrix Theory Conference (Pohang, 2002). Linear Algebra Appl. 373 (2003), 197-210. %H A001710 N. J. A. Sloane, Table of n, a(n) for n = 0..100 %H A001710 P. J. Cameron, Sequences realized by oligomorphic permutation groups, J. Integ. Seqs. Vol. 3 (2000), #00.1.5. %H A001710 Milan Janjic, Enumerative Formulas for Some Functions on Finite Sets %H A001710 INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 262 %H A001710 W. Lang, On generalizations of Stirling number triangles, J. Integer Seqs., Vol. 3 (2000), #00.2.4. %H A001710 Xah Lee, Combinatorics: Loop in n points %H A001710 Alexsandar Petojevic, The Function vM_m(s; a; z) and Some Well-Known Sequences, Journal of Integer Sequences, Vol. 5 (2002), Article 02.1.7 %H A001710 Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics. %H A001710 Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics. %H A001710 Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics. %H A001710 Eric Weisstein's World of Mathematics, Even Permutation %H A001710 Eric Weisstein's World of Mathematics, Odd Permutation %H A001710 Index entries for sequences related to factorial numbers %F A001710 a(n) = numerator(n!/2) and A141044(n) = denominator(n!/2). %F A001710 a(0) = a(1) = a(2) = 1; a(n)=n*a(n-1) for n>3. - Chad R. Brewbaker (crb002(AT)iastate.edu), Jan 31 2003 [Corrected by N. J. A. Sloane (njas(AT)research.att.com), Jul 25 2008] %F A001710 a(0) = 0, a(1) = 1; a(n) = sum k*a(k) for k = 1 to n-1. - Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Oct 29 2002 %F A001710 Stirling transform of a(n+1)=[1, 3, 12, 160, ...] is A083410(n)=[1, 4, 22, 154, ...]. - Michael Somos Mar 04 2004 %F A001710 First Eulerian transform of A000027. See A000142 for definition of FET. - Ross La Haye (rlahaye(AT)new.rr.com), Feb 14 2005 %F A001710 a(n)=sum{k=0..n, (-1)^(n-k-1)T(n-1, k)cos(pi(n-k-1)/2)^2}+0^n; T(n, k)=abs(A008276(n, k)). - Paul Barry (pbarry(AT)wit.ie), Apr 18 2005 %F A001710 E.g.f.: (2-x^2)/(2-2*x). E.g.f. of a(n+2),n>=0, is 1/(1-x)^3. %F A001710 a(n+1)= A136656(n,1)*(-1)^n, n>=1. %p A001710 seq(mul((k), k=3..n), n=0..20); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Sep 14 2007 %p A001710 a[ -1]:=1:a[0]:=1:a[1]:=1:for n from 2 to 50 do a[n]:=(a[n-1]*(n+1)^2) od: seq(sqrt(a[n]), n=-1..19); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Mar 09 2008 %p A001710 with (combinat):seq(count(Partition((n!+1)), size=2), n=0..20); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Mar 28 2008 %t A001710 f[n_]:=If[n>1,n,1];a=2;lst={1};Do[a=n*a-a;AppendTo[lst,f[a/4]],{n,2,5!}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), May 28 2009] %o A001710 (PARI) a(n)=if(n<2,n>=0,n!/2) %Y A001710 Cf. A000142, A049444, A049459. a(n+1)= A046089(n, 1), n >= 1 (first column of triangle). %Y A001710 A000153 [From Gary W. Adamson (qntmpkt(AT)yahoo.com), Dec 25 2008] %Y A001710 Contribution from Johannes W. Meijer (meijgia(AT)hotmail.com), Jun 18 2009: (Start) %Y A001710 Cf. A161739 (q(n) sequence). %Y A001710 (End) %Y A001710 Sequence in context: A062569 A089057 A077134 this_sequence A105752 A053532 A159867 %Y A001710 Adjacent sequences: A001707 A001708 A001709 this_sequence A001711 A001712 A001713 %K A001710 nonn,easy,nice %O A001710 0,4 %A A001710 N. J. A. Sloane (njas(AT)research.att.com). %E A001710 More terms from Larry Reeves (larryr(AT)acm.org), Aug 20 2001 %E A001710 Further from Simone Severini (ss54(AT)york.ac.uk), Oct 15 2004 Search completed in 0.002 seconds