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 A230961 Boustrophedon transform of factorials beginning with 1, cf. A000142. 4
 1, 3, 11, 50, 273, 1746, 12823, 106462, 986689, 10103074, 113309991, 1381835454, 18209834849, 257911743506, 3907538236631, 63066584719982, 1080340925760129, 19577690297352258, 374214932301757255, 7524626434657416286, 158783753482817132065 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 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(A109449(n,k)*A000142(k+1): k=0..n). E.g.f.: conjecture: (tan(x)+sec(x))/(1-2*x+x^2) = (1- 12*x/ (Q(0)+6*x+3*x^2))/(1-x)^2, where Q(k) = 2*(4*k+1)*(32*k^2+16*k - x^2-6) - x^4*(4*k-1)*(4*k+7)/Q(k+1) ; (continued fraction). - Sergei N. Gladkovskii, Nov 18 2013 a(n) ~ n! * n * (1+sin(1))/cos(1). - Vaclav Kotesovec, Jun 12 2015 PROG (Haskell) a230961 n = sum \$ zipWith (*) (a109449_row n) \$ tail a000142_list CROSSREFS Cf. A230960. Sequence in context: A162477 A115081 A103466 * A203166 A000254 A081048 Adjacent sequences:  A230958 A230959 A230960 * A230962 A230963 A230964 KEYWORD nonn AUTHOR Reinhard Zumkeller, Nov 05 2013 STATUS approved

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Last modified October 15 09:26 EDT 2018. Contains 316211 sequences. (Running on oeis4.)