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 A230955 Boustrophedon transform of nonprimes. 7
 1, 5, 15, 40, 114, 371, 1422, 6334, 32238, 184655, 1175454, 8231308, 62882262, 520416569, 4638303786, 44292536061, 451160065069, 4882696090609, 55951575728713, 676777708544967, 8617001415386120, 115200823068725262, 1613460678695102980, 23624702309844184487 (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)*A018252(k+1): k=0..n). MATHEMATICA cc = Select[Range[max = 40], !PrimeQ[#]&]; t[n_, 0] := cc[[n+1]]; t[n_, k_] := t[n, k] = t[n, k-1] + t[n-1, n-k]; a[n_] := t[n, n]; Array[a, cc // Length, 0] (* Jean-François Alcover, Feb 12 2016 *) PROG (Haskell) a230955 n = sum \$ zipWith (*) (a109449_row n) a018252_list CROSSREFS Cf. A230954, A000747, A000732, A230953. Sequence in context: A054888 A201157 A301980 * A038066 A306159 A113861 Adjacent sequences:  A230952 A230953 A230954 * A230956 A230957 A230958 KEYWORD nonn AUTHOR Reinhard Zumkeller, Nov 03 2013 STATUS approved

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Last modified February 18 09:15 EST 2020. Contains 332011 sequences. (Running on oeis4.)