The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A000754 Boustrophedon transform of odd numbers. 4
 1, 4, 12, 33, 96, 317, 1218, 5425, 27608, 158129, 1006574, 7048657, 53847420, 445643681, 3971876930, 37928628529, 386337833232, 4181155148673, 47912508680086, 579538956964241, 7378919177090244, 98648882783190305 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS a(n) = Sum_{k=0..n} A116666(n+1,k)*A000111(n-k). - Reinhard Zumkeller, Nov 02 2013 LINKS Reinhard Zumkeller, Table of n, a(n) for n = 0..400 Peter Luschny, An old operation on sequences: the Seidel transform J. Millar, N. J. A. Sloane and N. E. Young, A new operation on sequences: the Boustrophedon on transform, J. Combin. Theory, 17A 44-54 1996 (Abstract, pdf, ps). N. J. A. Sloane, Transforms Wikipedia, Boustrophedon transform FORMULA a(n) = Sum_{k=0..n} A109449(n,k)*(2*k + 1). - Reinhard Zumkeller, Nov 02 2013 E.g.f.: (sec(x) + tan(x))*exp(x)*(2*x+1). - Sergei N. Gladkovskii, Oct 30 2014 a(n) ~ n! * (Pi+1) * exp(Pi/2) * 2^(n+2) / Pi^(n+1). - Vaclav Kotesovec, Oct 30 2014 MATHEMATICA CoefficientList[Series[(Sec[x]+Tan[x])*E^x*(2*x+1), {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Oct 30 2014 after Sergei N. Gladkovskii *) t[n_, 0] := 2n + 1; t[n_, k_] := t[n, k] = t[n, k - 1] + t[n - 1, n - k]; a[n_] := t[n, n]; Array[a, 30, 0] (* Jean-François Alcover, Feb 12 2016 *) PROG (Haskell) a000754 n = sum \$ zipWith (*) (a109449_row n) [1, 3 ..] -- Reinhard Zumkeller, Nov 02 2013 CROSSREFS Cf. A005408. Sequence in context: A219092 A135254 A326804 * A317974 A119683 A331834 Adjacent sequences:  A000751 A000752 A000753 * A000755 A000756 A000757 KEYWORD nonn,nice,easy AUTHOR STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified August 8 08:24 EDT 2020. Contains 336293 sequences. (Running on oeis4.)