This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A005803 M1838 #115 Sep 08 2022 08:44:34 %S A005803 1,0,0,2,8,22,52,114,240,494,1004,2026,4072,8166,16356,32738,65504, %T A005803 131038,262108,524250,1048536,2097110,4194260,8388562,16777168, %U A005803 33554382,67108812,134217674,268435400,536870854,1073741764,2147483586 %N A005803 Second-order Eulerian numbers: a(n) = 2^n - 2*n. %C A005803 Starting with n=2, a(n) is the second-order Eulerian number <<n-1,1>> (see A008517). %C A005803 Also, number of 3 X n binary matrices avoiding simultaneously the right-angled numbered polyomino patterns (ranpp) (00;1), (01;0) and (01;1). An occurrence of a ranpp (xy;z) in a matrix A=(a(i,j)) is a triple (a(i1,j1), a(i1,j2), a(i2,j1)) where i1<i2, j1<j2 and these elements are in same relative order as those in the triple (x,y,z). - _Sergey Kitaev_, Nov 11 2004 %C A005803 This is the number of target DNA sequences of the correct length present after each successive cycle of the Polymerase Chain Reaction (PCR). The first two cycles produce 0 target sequences, there are 2 target sequences present after the third cycle, then 8 after the fourth cycle, and so forth. - _A. Timothy Royappa_, Jun 16 2012 %C A005803 a(n+2) = the row sums of A222403. - _J. M. Bergot_, Apr 04 2018 %D A005803 R. L. Graham, D. E. Knuth and O. Patashnik, Concrete Mathematics, 2nd ed. Addison-Wesley, Reading, MA, 1994, p. 270. %D A005803 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %H A005803 T. D. Noe, <a href="/A005803/b005803.txt">Table of n, a(n) for n=0..500</a> %H A005803 S. Bilotta, E. Grazzini, and E. Pergola, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL18/Grazzini/graz3.html">Enumeration of Two Particular Sets of Minimal Permutations</a>, J. Int. Seq. 18 (2015) 15.10.2. %H A005803 I. Gessel and R. P. Stanley, <a href="https://doi.org/10.1016/0097-3165(78)90042-0">Stirling polynomials</a>, J. Combin. Theory, A 24 (1978), 24-33. %H A005803 Jim Haglund and Mirko Visontai, <a href="http://hans.math.upenn.edu/~jhaglund/preprints/es-final.pdf">Stable multivariate Eulerian polynomials and generalized Stirling permutations</a>. %H A005803 Sergey Kitaev, <a href="http://www.emis.de/journals/INTEGERS/papers/e21/e21.Abstract.html">On multi-avoidance of right angled numbered polyomino patterns</a>, Integers: Electronic Journal of Combinatorial Number Theory 4 (2004), A21, 20pp. %H A005803 Sergey Kitaev, <a href="https://web.archive.org/web/20130625171839/http://www.ms.uky.edu/~math/MAreport/4-ser.ps">On multi-avoidance of right angled numbered polyomino patterns</a>, University of Kentucky Research Reports (2004). %H A005803 Sandi Klavžar, Uroš Milutinović and Ciril Petr, <a href="http://dx.doi.org/10.1016/j.exmath.2005.05.003">Hanoi graphs and some classical numbers</a>, Expo. Math. 23 (2005), no. 4, 371-378. %H A005803 James McClung, <a href="https://web.wpi.edu/Pubs/E-project/Available/E-project-051620-220950/unrestricted/Constructions_and_Applications_of_W-States.pdf">Constructions and Applications of W-States</a>, Bachelor Thesis, Worcester Polytechnic Institute (2020). %H A005803 Simon Plouffe, <a href="https://arxiv.org/abs/0911.4975">Approximations de séries génératrices et quelques conjectures</a>, Dissertation, Université du Québec à Montréal, 1992; arXiv:0911.4975 [math.NT], 2009. %H A005803 Simon Plouffe, <a href="/A000051/a000051_2.pdf">1031 Generating Functions</a>, Appendix to Thesis, Montreal, 1992. %H A005803 Sam Spiro, <a href="https://arxiv.org/abs/1810.00993">Ballot Permutations, Odd Order Permutations, and a New Permutation Statistic</a>, arXiv preprint arXiv:1810.00993 [math.CO], 2018 (A000246); Discrete Math, 343 (2020), article 111869. %H A005803 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (4,-5,2). %F A005803 G.f.: 1 + 2*x^3/((1-x)^2*(1-2*x)). a(n) = A008517(n-1, 2). - _Michael Somos_, Oct 13 2002 %F A005803 Equals binomial transform of [1, -1, 1, 1, 1, ...]. - _Gary W. Adamson_, Jul 14 2008 %F A005803 a(0) = 1 and a(n) = Sum_{k=0..n-3} ((-1)^(n+k+1)*binomial(2*n-1,k)*stirling1(2*n-k-3,n-k-2)), n=>1. - _Johannes W. Meijer_, Oct 16 2009 %F A005803 a(0)=1, a(1)=0, a(2)=0, a(n) = 4*a(n-1) - 5*a(n-2) + 2*a(n-3). - _Harvey P. Dale_, May 21 2011 %F A005803 a(n) = A000225(n+1) - A081494(n+1), n > 1. In other words, a(n) equals the sum of the elements in a Pascal triangle of depth n+1 minus the sum of the elements on its perimeter. - _Ivan N. Ianakiev_, Jun 01 2014 %F A005803 a(n) = A165900(n-1) + Sum_{i=0..n-1} a(i), for n > 0. - _Ivan N. Ianakiev_, Nov 24 2014 %F A005803 a(n) = A000225(n) - A005408(n-1). - _Miquel Cerda_, Nov 25 2016 %F A005803 E.g.f.: exp(x)*(exp(x) - 2*x). - _Ilya Gutkovskiy_, Nov 25 2016 %e A005803 G.f. = 1 + 2*x^3 + 8*x^4 + 22*x^5 + 52*x^6 + 114*x^7 + 240*x^8 + 494*x^9 + ... %p A005803 A005803:=-2*z/(2*z-1)/(z-1)**2; # conjectured by _Simon Plouffe_ in his 1992 dissertation. Gives sequence except for three leading terms %t A005803 Table[2^n-2n,{n,0,50}] (* or *) LinearRecurrence[{4,-5,2},{1,0,0},51] (* _Harvey P. Dale_, May 21 2011 *) %o A005803 (PARI) {a(n) = if( n<0, 0, 2^n - 2*n)}; /* _Michael Somos_, Oct 13 2002 */ %o A005803 (Haskell) %o A005803 a005803 n = 2 ^ n - 2 * n %o A005803 a005803_list = 1 : f 1 [0, 2 ..] where %o A005803 f x (z:zs@(z':_)) = y : f y zs where y = (x + z) * 2 - z' %o A005803 -- _Reinhard Zumkeller_, Jan 19 2014 %o A005803 (Magma) [2^n-2*n: n in [0..30]]; // _Wesley Ivan Hurt_, Jun 04 2014 %Y A005803 Equivalent to second column of A008517. %Y A005803 a(n) = A070313 + 1 = A052515 + 2. Bisection of A077866. %Y A005803 Equals for n =>3 the third right hand column of A163936. %Y A005803 Cf. A000918 (first differences). %Y A005803 Cf. A000079, A000325, A005843, A130102. %K A005803 nonn,easy,nice %O A005803 0,4 %A A005803 _N. J. A. Sloane_, _Simon Plouffe_