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 A133600 Row sums of triangle A133599. 3

%I

%S 1,4,7,16,28,64,112,256,448,1024,1792,4096,7168,16384,28672,65536,

%T 114688,262144,458752,1048576,1835008,4194304,7340032,16777216,

%U 29360128,67108864,117440512,268435456,469762048,1073741824,1879048192

%N Row sums of triangle A133599.

%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (0,4).

%F For even indexed terms, a(n) = 2^n. For odd indexed terms, a(n) = 7 * 2^(n-3).

%F G.f.: -x*(x+1)*(3*x+1)/(2*x-1)/(2*x+1). - _R. J. Mathar_, Nov 14 2007

%F a(n) = 4*a(n-2) for n > 3; a(1) = 1, a(2) = 4, a(3) = 7. [From _Klaus Brockhaus_, Nov 26 2009]

%e a(4) = 16 = sum of row 4 terms of triangle A133599 = (3 + 7 + 5 + 1).

%e a(4) = 16 = 2^4.

%e a(7) = 112 = 7 * 2^4 = 7 * 16.

%o (PARI) {vector(31, n, if(n==1, 1, if(n%2>0, 7*2^(n-3), 2^n)))} /* _Klaus Brockhaus_, Nov 26 2009 */

%Y Cf. A133599, A000302 (bisection), A002042 (bisection, n>2).

%K nonn,easy

%O 1,2

%A _Gary W. Adamson_, Sep 18 2007

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Last modified October 21 17:14 EDT 2019. Contains 328302 sequences. (Running on oeis4.)