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 A231179 Boustrophedon transform of nonnegative integers, cf. A001477. 8
 0, 1, 4, 12, 36, 120, 462, 2058, 10472, 59976, 381770, 2673374, 20422908, 169020852, 1506427678, 14385323610, 146527700944, 1585801332848, 18171944693586, 219803766565366, 2798628476670180, 37414906698747564, 524019526485293894, 7672827408344428242 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS a(n) = A231200(n) / 2. 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 transform, J. Combin. Theory, 17A 44-54 1996 (Abstract, pdf, ps). Wikipedia, Boustrophedon transform FORMULA a(n) = Sum_{k=1..n} k * A109449(n,k). E.g.f.: x*exp(x)*(sec(x)+tan(x)). (After Sergei N. Gladkovskii in A000660.) - Peter Luschny, Oct 28 2014 a(n) = A000660(n) - A000111(n). - Sergei N. Gladkovskii, Oct 28 2014 a(n) ~ n! * exp(Pi/2) * 2^(n+1) / Pi^n. - Vaclav Kotesovec, Jun 12 2015 MATHEMATICA a[n_] := n! SeriesCoefficient[x Exp[x] (1+Sin[x]) / Cos[x], {x, 0, n}]; Table[a[n], {n, 0, 23}] (* Jean-François Alcover, Jul 30 2018, after Peter Luschny *) PROG (Haskell) a231179 n = sum \$ zipWith (*) (a109449_row n) [0..] CROSSREFS Cf. A000737, A000660. Sequence in context: A192205 A055395 A113990 * A331717 A192010 A252697 Adjacent sequences:  A231176 A231177 A231178 * A231180 A231181 A231182 KEYWORD nonn AUTHOR Reinhard Zumkeller, Nov 05 2013 STATUS approved

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Last modified April 15 06:12 EDT 2021. Contains 342975 sequences. (Running on oeis4.)